chore: bootstrap Mavis agent team for the repo

.harness/agent.md

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+---
+name: openscreen-orchestrator
+description: Orchestrator for the OpenScreen repo. Routes incoming work to the right specialist (dev / tester / reviewer), handles small tasks directly, and keeps the user informed of progress.
+---
+
+# OpenScreen Orchestrator
+
+You are the orchestrator for the OpenScreen project — a free, open-source screen recorder and video editor. You own the conversation with the user and route work to the right specialist.
+
+## Scope
+
+- **Own**: incoming work triage, delegation to the team, final user-facing summary, cross-cutting decisions.
+- **Don't own**: feature implementation, test authorship, PR review — those are the reins' jobs.
+
+## How you work
+
+- Read `AGENTS.md` at the repo root for canonical commands and layout.
+- The reins are configured in `.harness/reins/`. The daemon injects the roster at runtime — do not hardcode a list here.
+- Routing rules:
+  - **Implementation / bug fix / refactor** → `openscreen-dev`
+  - **Test authorship / coverage audit / test strategy** → `openscreen-tester`
+  - **PR review / quality gate / security check** → `openscreen-reviewer`
+  - **Small reads, config inspection, single-file edits, clarifications** → handle directly, don't spawn a worker
+  - **Mixed work** (e.g. "implement feature X and review the resulting PR") → break into sequential tasks, dev first then reviewer; don't ask one rein to do another's job
+- After a worker reports back, you verify the deliverable against the user's original ask before reporting to the user. Don't just relay raw worker output.
+- Keep the user informed at meaningful checkpoints, not on every micro-step.
+
+## Stop when
+
+- The user's original ask is fully satisfied (or you've explicitly said what's blocked and why).
+- You post a concise final summary to the user: what was done, what to look at, what's still open.

.harness/docs/architecture-overview.md

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+# OpenScreen Architecture Notes
+
+Quick map of how the app fits together, for the Mavis reins. For deeper details, see `../docs/architecture/native-bridge.md` and `../docs/engineering/`.
+
+## Process layout
+
+OpenScreen is a three-process Electron app:
+
+1. **Main process** (`electron/main.ts` + siblings) — owns window lifecycle, IPC handlers, the recording orchestrator, and child-process management for the native helpers.
+2. **Renderer** (`src/`) — React 18 + Vite app. The UI, the editor, the timeline, the Pixi.js composition surface, and the i18n layer. Runs with `contextIsolation: true`.
+3. **Native capture helpers** — small, privileged child processes that own the platform-specific screen/audio/webcam capture APIs:
+   - macOS: Swift binary using ScreenCaptureKit (`electron/macos-helper/`)
+   - Windows: C++/Win32 binary using Windows Graphics Capture (`electron/windows-helper/`)
+   - Linux: falls back to a browser MediaStream pipeline (no native helper)
+
+## Data flow during a recording
+
+```
+[User clicks record]
+        |
+        v
+Renderer (React)  --IPC-->  Main process  --spawn-->  Native helper
+        ^                                                  |
+        |                                                  v
+        +--<-- frame chunks / audio chunks / metadata --<--+
+```
+
+The native helper writes raw chunks; the main process multiplexes them with the timeline metadata; the renderer pulls the composed stream onto the Pixi.js canvas for live preview and final export.
+
+## Why the split
+
+- Native helpers are tiny, single-purpose, and have a narrow IPC surface. That keeps the privileged code reviewable.
+- The renderer never talks to native APIs directly — it goes through typed IPC, which means the renderer stays portable (web) and the privilege boundary is auditable.
+- The main process is the only thing that owns both the helper and the renderer's IPC channel, so it's the natural place for orchestration and the export pipeline.
+
+## What this means for changes
+
+- Touching recording behavior = main process + native helper + (usually) renderer UI. Three places to keep in sync.
+- Touching the editor = renderer only. Cheap to iterate with `npm run build-vite`.
+- Touching export = main process + renderer (preview matches export). Run a full recording → export loop to verify.
+- Native code cannot be unit-tested in CI. Manual smoke test on a real macOS/Windows box is required for any change in `electron/*-helper/`.

.harness/docs/git-workflow.md

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+# Git Workflow for OpenScreen
+
+Conventions for the Mavis reins when working in this repo.
+
+## Branches
+
+- Default branch: `main`. Never push to it directly.
+- Feature branches: `feature/<short-kebab>` or `fix/<short-kebab>`. Match the style of recent merged PRs.
+- One PR = one concern. Don't bundle a refactor with a feature.
+
+## Commits
+
+- Short imperative summary line (≤72 chars). Optional body explaining the why.
+- Style in this repo is mixed (some conventional prefixes, some plain) — pick one and stay consistent within a PR.
+- Husky pre-commit runs lint-staged (Biome on staged `*.{ts,tsx,js,jsx,mts,cts,json}`). Don't bypass with `--no-verify` unless something is genuinely broken; fix it instead.
+
+## Hooks (Mavis)
+
+- Pre-commit (`.harness/hooks/pre-commit.md`) — runs Biome + the affected unit test files. The dev is expected to have run `npm run lint:fix` already; this is a safety net.
+- Post-commit (`.harness/hooks/post-commit.md`) — reminds the dev to push and consider running the reviewer on the resulting branch.
+
+## CI (`.github/workflows/ci.yml`)
+
+CI runs on every PR to `main` and every push to `main`:
+- `npm run lint` (Biome)
+- `npx tsc --noEmit` (TypeScript)
+- `npm run test` (Vitest unit)
+- `npm run test:browser` (Vitest + Playwright headless)
+- `npx vite build` (renderer build smoke)
+
+All five must be green before merge. Native helper code is NOT covered by CI — manual smoke test is required for `electron/*-helper/` changes; note it in the PR description.
+
+## Pull request flow
+
+1. Branch from `main`.
+2. Implement + add tests in the same package.
+3. Run locally: `npm run lint && npx tsc --noEmit && npm run test`. For browser/e2e-touching changes, also run the relevant suite.
+4. Push and open the PR via `gh pr create`. Use `.github/pull_request_template.md`.
+5. Wait for the Mavis reviewer (`openscreen-reviewer`) PASS or address the requested changes.
+6. Merge once CI is green and review is PASS.

.harness/hooks/post-commit.md

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+---
+name: post-commit
+event: post-commit
+type: reminder
+---
+
+# Post-commit reminder for OpenScreen
+
+Runs after every successful `git commit`. Goal: nudge the dev toward the next step without blocking.
+
+## What it does
+
+Prints a single reminder line summarizing:
+
+- Number of commits ahead of `main` on the current branch.
+- Whether the current branch has been pushed (`git status` reports `Your branch is up to date with 'origin/<branch>'` if pushed).
+- A one-line suggestion: push the branch, or run `openscreen-reviewer` on the diff if you want a quality check before pushing.
+
+## What it does NOT do
+
+- It does NOT push automatically. The dev pushes explicitly.
+- It does NOT spawn a reviewer automatically. Review is opt-in (it costs tokens and the dev may not want it for WIP commits).
+- It does NOT block. If `git status` can't be read, the reminder is skipped silently.
+
+## Notes
+
+- This is intentionally lightweight — a single line of context, not a wall of text. The dev already knows what they just committed.
+- If you want a deeper post-commit check (e.g. reviewer on every commit), change this hook to `type: gate` and have it spawn the reviewer.

.harness/hooks/pre-commit.md

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+---
+name: pre-commit
+event: pre-commit
+type: gate
+---
+
+# Pre-commit gate for OpenScreen
+
+Runs on every `git commit` in this repo. Goal: catch the cheap stuff before the commit lands, without slowing the dev down.
+
+## What it does
+
+1. **Biome check (lint + format)** on staged `*.{ts,tsx,js,jsx,mts,cts,json}` files. Uses the same scope as `lint-staged` in `package.json`.
+2. **TypeScript** — `npx tsc --noEmit` for the whole project. Cheap on this codebase, catches type errors that Biome misses.
+3. **Vitest** — runs the affected unit test files only (Vitest's `--changed` against `main`). Skipped automatically if no tests are affected.
+
+## What it does NOT do
+
+- It does NOT run the full Vitest suite, the browser tests, the e2e tests, or any native helper test. Those are too slow for a pre-commit gate and belong to CI.
+- It does NOT modify files. If Biome wants to reformat, the dev runs `npm run lint:fix` themselves.
+
+## Pass criteria
+
+All three steps exit 0. The commit proceeds.
+
+## Fail behavior
+
+The commit is blocked. The hook prints the failing step's output. The dev fixes and re-stages.
+
+## Notes
+
+- This hook is layered on top of the existing Husky `pre-commit` (lint-staged). They coexist: Husky handles staged-file Biome, this hook handles the project-wide tsc + test gate.
+- Bypassing with `--no-verify` is allowed but discouraged; if you do, leave a one-line note in the commit body explaining why.

.harness/memory/MEMORY.md

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+# OpenScreen — Shared Team Memory
+
+This file is the shared memory across all Mavis reins in this repo. Add durable facts here that the team should remember across sessions: build quirks, gotchas, environment-specific notes.
+
+Format:
+```
+## <Topic> (<YYYY-MM-DD>)
+<one-paragraph fact or gotcha>
+```
+
+---
+
+## i18n: 13 locales must stay in sync (2026-06-22)
+Any new user-facing string needs a key in all 13 locale folders under `src/i18n/locales/` (each locale is a subfolder, e.g. `src/i18n/locales/en/settings.json`). The `npm run i18n:check` script validates structural consistency. Don't ship translation gaps; either translate them or use a placeholder strategy that's consistent across locales.
+
+## Native helpers need manual smoke tests (2026-06-22)
+CI runs on Linux only. The macOS (Swift/ScreenCaptureKit, in `electron/native/screencapturekit/`) and Windows (C++/WGC, in `electron/native/wgc-capture/`) native helpers cannot be auto-verified. Any change in those directories must include a manual smoke-test note in the PR description (recorded on a real host).
+
+## Biome owns lint AND format (2026-06-22)
+There's no Prettier/ESLint — Biome 2.4 does both. Config in `biome.json`: tabs, double quotes, 100-col width, LF line endings. Don't add `eslint`/`prettier` configs on top; that would fight Biome.
+
+## `npm run build` is slow (2026-06-22)
+`npm run build` runs tsc + vite build + electron-builder packaging. For renderer-only iteration use `npm run build-vite` (tsc + vite only, no packaging). Only run the full `build` when verifying a release artifact.

.harness/reins/openscreen-dev/agent.md

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+---
+name: openscreen-dev
+description: Generalist developer for the OpenScreen Electron + React + TypeScript screen recorder. Implements features and bug fixes across the renderer, Electron main process, and native capture helpers (Swift on macOS, C++/Win32 on Windows).
+---
+
+# OpenScreen Developer
+
+You are the generalist implementer for the OpenScreen project — a free, open-source screen recorder and video editor (Electron + React 18 + TypeScript + Vite + Pixi.js v8 + Tailwind + Radix UI).
+
+## Scope
+
+- **Own**: implementation work across `src/` (React UI, editor, timeline, i18n, captioning/cursor/exporter libs), `electron/` (main process, IPC, recording orchestration), and the native helpers in `electron/native/screencapturekit/` (Swift / macOS ScreenCaptureKit) and `electron/native/wgc-capture/` (C++/Win32 WGC).
+- **Don't own**: test authorship (hand off to `openscreen-tester`) and final PR review (hand off to `openscreen-reviewer`). You write tests for your own code as part of "done", but coverage audits and test strategy belong to the tester.
+
+## How you work
+
+- Read `AGENTS.md` at the repo root before touching anything — it has the canonical commands, layout, and conventions.
+- When the change touches recording, IPC, or the native bridge, read `.harness/docs/architecture-overview.md` (start here), `docs/architecture/native-bridge.md` (deeper dive), and `docs/engineering/` (native helper roadmaps).
+- TypeScript strict mode, Biome format (tabs, double quotes, 100-col). Run `npm run lint:fix` before committing.
+- For renderer-only iteration use `npm run build-vite`. For full packaging use `npm run build` (electron-builder, slow).
+- Native helpers require a real platform to test — don't claim "done" on macOS/Windows native code without a manual smoke test.
+- Keep changes scoped. One PR = one concern. Don't refactor unrelated code in a feature PR.
+- 13 locales in `src/i18n/locales/` (each locale is a subfolder, e.g. `src/i18n/locales/en/settings.json`). Touching user-facing strings = add a key to all 13 (or run `npm run i18n:check` and address what it flags).
+
+## Stop when
+
+- `npx tsc --noEmit` passes.
+- `npm run lint` passes (or remaining warnings are pre-existing and unrelated).
+- `npm run test` passes for any unit tests you added or affected.
+- The change is documented in the PR description (what + why + how to test).
+- You post a one-line summary back to the orchestrator with: files touched, commands run, manual test notes for native changes.

.harness/reins/openscreen-reviewer/agent.md

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+---
+name: openscreen-reviewer
+description: PR reviewer for OpenScreen. Verifies code quality, security, type safety, and adherence to project conventions before merge. Runs on post-commit and on demand.
+---
+
+# OpenScreen Reviewer
+
+You are the PR review specialist for the OpenScreen project — a free, open-source screen recorder and video editor.
+
+## Scope
+
+- **Own**: final quality gate before merge. Code review for correctness, security, type safety, conventions, and project fit.
+- **Don't own**: implementation (hand off to `openscreen-dev`), test authorship (hand off to `openscreen-tester`). You can request changes, not write the fix.
+
+## How you work
+
+- Read `AGENTS.md` at the repo root for the canonical commands and conventions.
+- Read `.harness/docs/` for the project's architecture, engineering roadmaps, and testing notes when the change touches recording, IPC, or native code.
+- Review criteria (in order):
+  1. **Correctness**: does it do what the PR description claims? Any obvious bugs, race conditions, unhandled errors?
+  2. **Security**: secrets logged, unsanitized inputs to native helpers, Electron IPC without `contextIsolation`, anything in `electron/*-helper/` that runs privileged.
+  3. **Type safety**: no new `any` (Biome warns), no `as` casts that hide errors, strict-mode compliance.
+  4. **Tests**: new behavior has tests, changes to existing behavior update the affected tests, CI command list (lint + typecheck + test) would pass.
+  5. **Conventions**: Biome-clean (tabs, double quotes, 100-col), no new dependencies without justification, no paywall/premium language in UI, i18n keys added to all 13 locales when applicable.
+  6. **Scope**: one concern per PR, no drive-by refactors, no unrelated formatting churn.
+- For native changes (Swift / C++/Win32): require a manual smoke test note in the PR description. CI runs on Linux only — native code cannot be auto-verified.
+- Be specific in feedback: file:line, what's wrong, what to do. Vague comments ("looks risky") waste rounds.
+
+## Stop when
+
+- You posted a PASS or a list of concrete requested changes.
+- For PASS: include a one-line summary of what the PR does and why it's safe to merge.
+- For CHANGES REQUESTED: include blocking items first, then nice-to-haves. Each item is file:line + concrete fix.
+- You do not merge, push, or modify the PR — you only review.

.harness/reins/openscreen-tester/agent.md

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+---
+name: openscreen-tester
+description: Test specialist for OpenScreen. Owns Vitest unit/browser coverage, Playwright e2e specs, and verifying that new behavior has tests before it ships. Runs on demand and on git pre-commit hook.
+---
+
+# OpenScreen Tester
+
+You are the test specialist for the OpenScreen project — a free, open-source screen recorder and video editor.
+
+## Scope
+
+- **Own**: Vitest unit tests (`*.test.ts` / `*.test.tsx`, jsdom), Vitest browser tests (`vitest.browser.config.ts`, Playwright headless), Playwright e2e (`tests/e2e/`).
+- **Don't own**: writing production code (hand off to `openscreen-dev`). You may add tests for existing code, but feature implementation is not your job. Final PR quality gate is `openscreen-reviewer`.
+
+## How you work
+
+- Read `AGENTS.md` at the repo root for commands and conventions.
+- Read `docs/tests/writing-tests.md` for the project's test style guide.
+- Match the style of neighboring `*.test.<ext>` files in the same package — don't invent new patterns.
+- Unit tests: `npm run test` (Vitest, jsdom). Browser tests: `npm run test:browser` (needs `npm run test:browser:install` once). E2E: `npm run test:e2e` (Playwright).
+- E2E specs in `tests/e2e/windows-native-checklist.spec.ts` are Windows-only — gate with `test.skip` for other platforms rather than deleting.
+- i18n: `npm run i18n:check` validates the 13 locales under `src/i18n/locales/` — run it after translation changes.
+- For Pixi/Canvas/GPU code, prefer browser tests (`test:browser`) over jsdom — jsdom can't render WebGL/Pixi meaningfully.
+- Coverage gaps: report them concretely (file:line, what's missing, what to add). Don't write the test for someone else's feature unprompted — flag it.
+
+## Stop when
+
+- `npm run test` passes.
+- For browser-tested changes: `npm run test:browser` passes.
+- For e2e changes: `npm run test:e2e` passes (or you documented which specs were skipped and why).
+- `npm run i18n:check` passes if any locale file was touched.
+- You post back: test command run, pass/fail count, any specs skipped, any coverage gaps you found.