feat(m12): generator spike — grow a playable planet from the pair's rhythm

[ksdisch]

What & why

The next step of the project's boldest vision, "The Planet That Knows You Two": stop hand-authoring planets and grow one from a recorded portrait of how this specific pair plays. M10 shipped the de-risked wedge (schema-v2 per-role solve telemetry + the read-only portrait card); nothing yet consumed that telemetry. This spike closes that gap — telemetry → a PlanetConfig you can actually play.

The honest risk the vision doc names is that a generator "dynamites the rigid PlanetConfig" the codebase's safety rests on — "one bad planet ruins the evening." So the crux deliverable here isn't a generated planet, it's a proof the generator can never emit an unplayable one.

Changes

• New src/game/planets/generate.ts (pure, deterministic):
  • deriveProfile(telemetry) → RhythmProfile — aggregates the pair's recorded rhythm (solve speed, respawn history, explore-vs-solve split) into normalized 0..1 signals + a stable seed. Never throws; empty/solo/corrupt telemetry → a neutral default.
  • generatePlanet(profile) → PlanetConfig — maps those signals to geometry knobs, each clamped to a band proven valid against the shared reach budget, so the output is always clearable. Seeded mulberry32 for within-band variety (no Date.now/Math.random, per the Vitest determinism guards). Themeless (default textures, zero Boot churn); planet-3 gate template (Freeze corridor → Phase Dash curtain → Illuminate finale).
• New src/game/planets/generate.test.ts — the safety proof: a property sweep of 1000 configs (profile grid × seeds) plus corrupt/extreme inputs, asserting every generated config satisfies the same invariants planet3.test.ts encodes (full-height curtain, Illuminate finale reach math, in-canvas keypoints, degenerate-or-≥260 pit); determinism; and deriveProfile never throwing on a hostile blob.
• src/game/scenes/Hub.ts — a "✦ Grow a planet" node derives from loadProgress().telemetry and launches the generated config via scene-data (Planet.init takes a raw config, so no registry mutation, no progression coupling).
• src/game/testBridge.ts — adds startGeneratedPlanet() so a headless driver can clear a grown planet through the usual getState/cast/input loop.

Verification

• npm run typecheck ✓ · npm run test 168 passed (+12 new) ✓ · npm run build ✓ · npm run smoke:relay ✓
• Headless full clear of a generated planet (pre-installed Chromium, ?solo=1&test=1): startGeneratedPlanet() → boots into the Planet scene → Freeze freezes the sentry → Phase Dash crosses the curtain → Illuminate reveals the ledge → reaches the goal. won=true, 0 respawns, win cue fired, telemetry recorded (attempts:1, lastClearMs:4881).

Deliberate spike cuts

• Themeless — theme selection needs Boot preload textures; noted follow-up.
• One gate template (planet-3's) — proving the pipeline, not a template library.
• Not a registry/progression node — a launch target only; it doesn't record telemetry back (keeps the spike one-way: telemetry → planet).
• No protocol/relay/src/shared/phone/dependency changes.

Does the grown planet feel like ours? That's the human gate the vision doc names — the spike earns the right to ask it, it can't self-answer it.

🤖 Generated with Claude Code

https://claude.ai/code/session_01Pm5HnAqLxtzGYMo6cFxRrt

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Generated by Claude Code

[ksdisch]

Closing per 2026-08-01 PR triage: M12 generator spike idle since 2026-07-12, mergeable state unknown. The spike's value is the recorded design in the PR body, which survives closure. The branch survives if this is ever picked back up.