feat: add pause and resume goal commands

[danyel117]

Summary

• register standalone /pause_goal and /resume_goal server commands in OpenCode V1 and V2 for remote integrations that expose the server command catalog
• persist /pause_goal before its acknowledgement turn, then cancel scheduled/watchdog continuations so later idle events cannot restart the goal
• remove dedicated-command arguments and resolved attachments from the model prompt while preserving the main /goal forwarding behavior
• preserve user-defined command collisions and keep V2 transforms stable across registry replay
• reserve the standalone names when command_name is configured so all three controls remain available
• make status transitions idempotent, preserve safety-limited states on pause, and reject reopening closed goals
• document supported remote integrations, OpenCode V1 argument preprocessing, and already-delivered/in-flight continuation limitations

Verification

• bun run lint
• bun run typecheck
• bun test (230 passing; one pre-existing timing test was rerun after a transient failure and the complete suite then passed)
• bun run build
• bun run pack:dry-run
• internal standards review: approved
• internal issue/spec review: approved
• Claude Opus round 1: requested pause/cancel ordering, accurate acknowledgement wording, and V1 preprocessing documentation; fixed in 5ac71e4

Closes #36

AI assistance: implemented and reviewed with OpenCode agents and independently reviewed with Claude Opus.

[danyel117]

Claude Opus final review: APPROVE.

The first review requested three corrections: persist the pause before cancelling timers, acknowledge the pre-applied pause accurately, and document OpenCode V1 command preprocessing precisely. Commit 5ac71e4 resolves all three.

Opus independently verified the pinned V2 prompt/tool context contracts, V1 command hook behavior, command ownership and replay safety, Plan-mode enforcement, lifecycle guards, generated bundle reproducibility, package contents, and the full local gate: 230 tests, lint, typecheck, build, and pack. No merge-blocking findings remain.