feat: list goals across sessions

[danyel117]

Summary

• add getAllGoals and the V1/V2 list_all_goals tool
• return up to 50 cross-session summaries ordered by recent updates, with total and truncated metadata
• expose only an allowlisted summary projection, excluding histories, messages, checkpoints, evidence, blockers, and internal state
• report persisted elapsed time for foreign sessions and keep listing read-only for progress/retry accounting
• keep cross-session results out of the current-session TUI indicator

Validation

• bun run lint
• bun run typecheck
• bun test (212 pass)
• bun run build
• bun run pack:dry-run
• two Claude Opus review rounds; final result: no merge blocker

Closes #3