feat: complete core extraction and runtime hardening

[im10furry]

Summary

• Complete the Strangler-Fig extraction from packages/core into focused workspace packages and align aliases, manifests, lockfile, build entrypoints, and package-boundary checks.
• Harden model/runtime/tool flows: Responses API schemas, OpenAI retry/cancellation, Codex OAuth bridging, read-mode tool controls, daemon permission/session behavior, and background goal scheduling.
• Improve CLI/TUI workflows for Copilot login activation, reasoning effort, goals and status, voice commands, prompt paste safety, grouped messages, and tool presenters.
• Add regression coverage and fault-review documentation; retain the existing task-persistence and F10 voice commits as separate history.

Validation

• bun run check
• bun run cli -- --help
• Dependency-graph and package-boundary test coverage are included in the full suite.

Review notes

• The extraction is intentionally atomic: packages and consumers move together so intermediate commits do not leave invalid workspace boundaries.
• No credentials were added; the only key-like strings are documented placeholders.