Add task drop and restore status mutations

[deverman]

Closes #129

Summary

• add edit_tasks set_status with active and dropped states
• require explicit occurrence or series scope for repeating drops
• preflight complete batches before writes and report already-satisfied targets as unchanged
• return normalized taskStatus, dropDate, and completionDate for verification
• add CLI parity, MCP wire coverage, deterministic JavaScriptCore contracts, live-test scaffolding, and user documentation

Validation

• swift run focusrelay-dev validate --impact mutation
• 154 Swift Testing tests passed
• clean release build passed
• installed bridge health check passed after the required OmniFocus restart
• git diff --check

Live UAT

Passed 2026-07-23 against the explicitly disposable active, non-repeating task gLQq6L9uLDn:

• non-writing drop preview passed
• invalid recurrence scope was rejected atomically for the non-repeating fixture
• drop with verification returned taskStatus=dropped, a non-null dropDate, and completionDate=null
• restore with verification returned taskStatus=active, dropDate=null, and completionDate=null
• formal taskStatusDropVerifyRestoreLive Swift Testing case passed

The fixture was restored to its original active lifecycle state.