Implement move_tasks for homogeneous bulk moves

[deverman]

Summary

• implement move_tasks across the shared mutation core, CLI, MCP, and bridge plugin
• validate and execute homogeneous bulk task moves to inbox, project, or parent task destinations
• add mutation validation and CLI/core tests for move-specific constraints

Testing

• node --check Plugin/FocusRelayBridge.omnijs/Resources/BridgeLibrary.js
• swift test
• ./scripts/install-plugin.sh
• osascript -e 'tell application "OmniFocus" to quit' && sleep 2 && open -a "OmniFocus"
• swift run focusrelay bridge-health-check
• swift run focusrelay move-tasks e-Wn5k27h6g --destination-kind inbox --preview-only --verify --return-fields id,name,projectName
• swift run focusrelay move-tasks e-Wn5k27h6g --destination-kind inbox --verify --return-fields id,name
• swift run focusrelay move-tasks e-Wn5k27h6g --destination-kind project --destination-id l6ZI4Q1HqpK --verify --return-fields id,name,projectName

[deverman]

Stack note: this draft PR is based on issue-31-set-tasks-completion / PR #42, not master.

Merge order for the stack:

1. Add shared mutation core preview pipeline #40
2. Implement update_tasks mutation flow #41
3. Implement set_tasks_completion lifecycle flow #42
4. Implement move_tasks for homogeneous bulk moves #43

After #42 merges, retarget or rebase #43 onto the updated base before final merge if needed.

[deverman]

Follow-on branch note: issue #33 is now being implemented on top of this PR in branch issue-33-update-projects-and-status.

Expected merge order remains:

1. Add shared mutation core preview pipeline #40
2. Implement update_tasks mutation flow #41
3. Implement set_tasks_completion lifecycle flow #42
4. Implement move_tasks for homogeneous bulk moves #43
5. Implement update_projects and set_projects_status #44 (forthcoming for Implement update_projects and set_projects_status #33)