refactor(core): centralize session lifecycle composition

[ElbertePlinio]

Refs #44 — implements CAND-1 only.

Summary

• add one deep core lifecycle module for recipe validation/expansion, ordered leg creation, desktop rollback, typed destroy dispatch, destroy-all continuation, and canonical live-status aggregation
• inject typed desktop-linux, Android, and browser runtime adapters while keeping browser display ownership intact
• keep CLI rendering/viewer behavior and MCP schemas/evidence/status decoration adapter-specific
• add focused lifecycle characterization tests for ordering, rollback, cancellation, browser ownership, status aggregation, and partial destroy failures

CAND-2 remains out of scope. Its preferred placement can now build on the typed runtime teardown seam established here without changing adapter contracts.

Validation

• bun run test packages/core/test — 260 passed
• bun run test packages/browser/test — 110 passed
• bun run test packages/android/test — 99 passed
• bun run test packages/desktop-linux/test — 79 passed, 2 skipped
• bun run test packages/mcp-server/test — 100 passed
• bun run test packages/cli/test — 195 passed
• bun run typecheck
• bun run build
• focused CLI/MCP output and resource tests passed
• local correctness/conformance/KISS review: clean