fix(opencode): add chokidar fallback for file watcher (#132)

[randomm]

Summary

• Adds chokidar fallback when @parcel/watcher native module fails to load
• Enables file watching in bundled oclite binary
• Adapts chokidar events to @parcel/watcher format

Fixes#132

[github-actions]

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2. Add Fixes #<number> or Closes #<number> to this PR description

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[randomm]

Code Review Findings

⚠️ CRITICAL ISSUES

1. Type System Inconsistency (Lines 35, 63-64)

// Line 35: Return type is now non-nullableconstwatcher=lazy((): typeofimport('@parcel/watcher')=>{// ...always returns value (native or chokidar)})// Lines 63-64: This check is now UNREACHABLEconstw=watcher()if(!w)return{}// ❌ w can never be undefined

Fix: Remove the if (!w) return {} check

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2. Race Condition in Error Handling (Lines 45, 54-56)

watcher.once('ready',()=>{resolve({/* ... */})})watcher.once('error',(err)=>{// ⚠️ Race conditionreject(err)})

If error fires after 'ready', the reject handler may cause unhandled rejection.

Fix: Remove error listener after successful ready:

constonError=(err: unknown)=>reject(...)watcher.once('ready',()=>{watcher.off('error',onError)resolve({/* ... */})})watcher.once('error',onError)

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3. Backend Option Ignored
Chokidar adapter doesn't handle backend option that's passed at lines 81, 103. This could confuse users about expected behavior.

Fix: Document this limitation or handle the backend option appropriately.

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📋 RECOMMENDATIONS

4. Log Level Inconsistency

• Use log.warn('Native watcher unavailable, using chokidar fallback') instead of log.info
• Makes troubleshooting clearer

5. Chokidar Availability Check

• Wrap chokidar usage in try-catch to handle case where it's also missing
• Provide helpful error message

6. Error Handling in Cleanup

• Log errors from watcher.close() instead of silently swallowing them

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Event Mapping: ✅ Correct
Interface Compliance: ✅ Proper
Memory Management: ⚠️ Needs error logging

Critical issues #1-3 should be addressed before merge.