feat: complete timed workout and training archive workflow

[lagrangee]

Summary

This PR completes the timed workout execution flow and the structured training archive workflow.

What changed

• Added timed workout execution feedback, audio cues, rest/tempo controls, wake-lock and foreground recovery, and stale/expired session handling.
• Added structured Workout/COROS training archive projections, route registry/history, Agent API reads and writes, and reliable sync boundaries.
• Added local/private archive handling with D1 cloud projections while preserving source status, privacy boundaries, and idempotent activity identity.
• Added records, strength, aerobic activity, route history, calendar, and related UI refinements.
• Added contract updates, issue/spec documentation, and focused regression coverage.

Root cause

The previous branch had separate pieces of the timed-session and training-archive workflows, but lacked a complete end-to-end implementation and consistent read/write boundaries. This PR connects those pieces and hardens the lifecycle, synchronization, and presentation paths.

Validation

• npm run release-check
• Typecheck passed.
• 155/155 tests passed.
• Seed verification passed.
• Forbidden-feature scan passed.
• Local release acceptance passed.
• Production UI verification completed for records spacing and aerobic route alignment.

Target branch: main.