[FEATURE] Offline queue and sync recovery for the plugin

[aernw]

Objective

Make plugin workflows more resilient when connectivity is unreliable.

Scope

• queue commit or sync intents when connectivity is unavailable
• surface pending and recovered sync states in the plugin
• support clearer recovery from delayed network operations

Out of Scope

• [Features explicitly not included]
• [Future enhancements to defer]

Acceptance Criteria

• the plugin behaves more gracefully when the network is imperfect
• users can understand what is pending, synced, or failed without guesswork

Dependencies

Blocked by: (none)

Blocks: (none)

Success Metrics

• [How to measure success - optional]

Roadmap Context

Milestone: M7 - Launch Readiness & Cross-DAW Expansion
Parent workstream(s): #213