fix(watcher): add debounce to prevent duplicate IPC actions - #78

Summary

Fixes duplicate browser windows and notifications when OpenCode writes to IPC files multiple times per action.

Problem

When OpenCode triggers IPC events (e.g., opening WebUI, sending notifications), it writes to IPC files 7-11 times per action due to internal implementation. The OCD watcher had a race condition:

1. Read content from file
2. Execute side-effect (slow - e.g., open command)
3. Clear file

This allowed subsequent writes to trigger additional executions before the file was cleared.

Solution

Atomic Consumption

Changed order to: read → clear → execute

This ensures the file is cleared before the slow side-effect runs, preventing race conditions.

Debounce Logic

• URL handler: 3-second window, same URL = skip
• Notification handler: 3-second window, same content hash = skip

State stored in /tmp/.ocd_ipc_state/ with timestamp + content tracking.

Changes

• lib/watcher.sh: Added atomic consumption + debounce to ocd_handle_url and ocd_handle_notify
• tests/bats/watcher.bats: Added 6 new tests for debounce behavior

Testing

# Run tests on Mac
bats tests/bats/watcher.bats

# Manual test
devocd -r  # Rebuild with fix
# In TUI: Cmd+O to open WebUI → should only open 1 window