feat(memory): add agent_memory table and memory-tools plugin

[herjarsa]

Issue for this PR

Closes # (new feature, no issue)

Type of change

• New feature

What does this PR do?

Adds the �gent_memory table and memory-tools plugin for cloud backup/restore of OpenCode AgentMemory via Supabase.

Changes:

1. �gent_memory table with FTS5 full-text search and tags support
2. AgentMemory service in Effect (save, search, consolidate)
3. memory-tools plugin with 5 tools:
   • memory.configure - Configure Supabase connection
   • memory.backup - Push local memories to cloud
   • memory.restore - Pull cloud memories to local (merge)
   • memory.status - Show sync status
   • memory.schedule - Get/set auto-sync interval

Cloud sync features:

• Conflict resolution: newest wins by timestamp
• Auto-scheduler with configurable intervals (5m, 15m, 1h, 1d, manual)
• Works with existing OpenCode AgentMemory data

How did you verify your code works?

• TypeScript compiles without errors in memory-tools package
• All Bun.sqlite bindings use proper type casts
• Plugin follows the correct Plugin interface from @opencode-ai/plugin
• Code follows OpenCode module conventions (Effect, self-export pattern)

Checklist

• I have not included unrelated changes in this PR

[github-actions]

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