chore: Replace PR linter workflow with AGENTS.md instructions (#25)

Co-authored-by: Paperclip <noreply@paperclip.ing>

Author: DaveSkender

.github/workflows/lint-pull-request.yml

@@ -0,0 +1,12 @@
+# stockindicators.dev
+
+Simple landing page for the stockindicators.dev domain — a developer menu site linking to Stock Indicators SDK packages for various languages.
+
+## Pull request conventions
+
+PR titles must follow Conventional Commits format: `type: Subject`
+
+- `type` is lowercase: `feat`, `fix`, `docs`, `style`, `refactor`, `perf`, `test`, `build`, `ci`, `chore`, `revert`, `plan`
+- `Subject` starts with an uppercase letter; keep total title length ≤ 65 characters
+
+Ignore this convention for PRs labeled `bot`, `dependencies`, or `automated`.