Port Goal lifecycle --notify hook onto current main

[ByBrawe]

Ports the useful design from contributor PR #196 onto the post-1.3.33/current-main persistence and runtime architecture. Credit to @rubenxyz for the original --notify proposal and implementation direction.

Part of #201.

Contract

• /goal ... --notify "<command>" stores an optional user-authored lifecycle command.
• {goal} expands to the Goal ID.
• {reason} is completed, blocked, paused, or rejected.
• waiting_user, budget-limited, and usage-limited states map to paused.
• queued Goals preserve the command through promotion; /goal edit preserves it unless explicitly replaced.

Safety / current-main invariants

• Notification dispatch happens only after durable Goal persistence.
• Suppress semantic no-op GoalStore writes #202 semantic no-op saves do not emit notifications or advance storage generation.
• Same-status semantic updates do not duplicate lifecycle notifications.
• Notification failures are advisory and cannot roll back Goal state/completion.
• Persisted notifyCommand is validated fail-closed.
• Persist runtime fingerprints for Goal diagnostics #203 runtime fingerprint stamping/validation remains intact.
• Model-facing opencode_goal_* tool schemas expose no notifyCommand mutation field; configuration stays on the user-authored Goal Contract command surface.
• The current waiting-user, budget/usage, restart recovery, restricted-agent, host-limit and completion paths are wired through the current persistence architecture rather than copying the old pre-1.3.32 store layout.

Tests

• parser/multiline/malformed contract behavior
• persisted create/edit validation
• post-persistence lifecycle emission + no-op/same-status suppression
• callback failure cannot break persistence
• paused restore notification
• spawn substitution/failure behavior
• queued Goal preservation/promotion
• rejected completion classification
• model-facing Goal tool schema ownership boundary

Supersedes the old implementation branch only after this current-main port passes the full required CI/real-host/release-readiness gates.

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