docs: add commit style instructions for agents

AGENTS.md

@@ -0,0 +1,19 @@
+# AGENTS
+
+## Commit Style
+
+- Use Conventional Commits for every commit message.
+- Required format: `type(scope): subject` or `type: subject`.
+- Keep `type`, optional `scope`, and subject text lowercase.
+- Use imperative, concise subjects.
+- Proper nouns may keep their normal capitalization only when necessary.
+
+Valid examples:
+- `feat(ui): add artist text truncation`
+- `fix: handle empty metadata values`
+- `chore(release): bump plasmoid version`
+
+Invalid examples:
+- `Feat(ui): add artist text truncation` (uppercase type)
+- `fix(UI): handle empty metadata values` (uppercase scope)
+- `fix: Handle empty metadata values` (uppercase subject)