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)

[deverman]

Maintainer validation note for #43:

• Merge order: this PR is now retargeted to master after Implement set_tasks_completion lifecycle flow #42 was merged. It is the next roadmap PR before Implement update_projects and set_projects_status #44 update_projects and set_projects_status.
• Local validation passed: node check for BridgeLibrary.js, swift test with 82 Swift Testing tests, git diff --check, plugin install plus full OmniFocus restart, bridge-health-check, and benchmark-gate-check for task-counts, list-tasks, and project-counts.
• Live mutation validation passed for task mveToEQy4AJ: preview-only project move, preview-only inbox move, preview-only parent task move, real project move to Leave DFS with verify, and real restore to Personal single actions with verify.
• I found and fixed a bridge bug where move_tasks verified and built returnedFields before save. That could report a stale successful inbox result if OmniFocus cleanup changed the saved destination. The branch now saves before verify/readback for real moves.
• I also compacted mutation returnedFields so requesting id,name,projectID,projectName returns only those keys instead of the whole sparse task payload full of nulls.
• Product note: on my OmniFocus setup, a real move to inbox can be auto-cleaned into the default single-action project Personal single actions after save/restart. The new save-before-verify behavior makes that visible instead of claiming stale inbox verification.