🐛 fix(generateCommitMsg): enhance error handling and logging for API failures

[adihanifsdr]

Summary

• Add a Logger class with a VSCode Output Channel (AI Commit) for structured, timestamped logging (INFO/WARN/ERROR)
• Replace all console.error() calls with Logger.error() across the codebase so logs appear in the Output panel instead of only the Developer Tools console
• Add info-level logging for key operations: extension activation, command execution, AI provider selection, and successful commit message generation
• Fix error handling in generateCommitMsg: preserve the original err.message instead of always showing "An unexpected error occurred", and also check err.status (newer OpenAI SDK) in addition to err.response?.status

Changes

File	Change
src/logger.ts	New — Logger class with VSCode OutputChannel, Error serialization support
src/extension.ts	Initialize/dispose Logger, log activation lifecycle
src/commands.ts	Log command execution and failures
src/generate-commit-msg.ts	Log API provider, success/failure; fix error swallowing
src/config.ts	Replace console.error with Logger.error
src/git-utils.ts	Replace console.error with Logger.error
src/gemini-utils.ts	Replace console.error with Logger.error

How to view logs

1. Open the Output panel: Ctrl+Shift+U
2. Select "AI Commit" from the dropdown
3. Logs appear with timestamps and level indicators

Test plan

• Verify "AI Commit" appears in the Output panel dropdown after activation
• Trigger a commit message generation and confirm INFO logs appear
• Trigger an API error and confirm the full error message and stack trace appear in the Output panel
• Confirm the error notification now shows the actual error message instead of "An unexpected error occurred"

[adihanifsdr]

Please check @Sitoi