docs: add project guidelines and commit conventions

- Add AGENTS.md with tech stack, project structure, and code styles
- Add dev/docs/dashboard.md with frontend-specific guidelines
- Include conventional commit types with examples

Co-authored-by: Ona <no-reply@ona.com>

dev/docs/dashboard.md

@@ -0,0 +1,19 @@
+# Context
+
+- tech stack: react, tailwindcss, shadcn, tanstack router, tanstack table, jotai
+- `@/` maps to `src/`
+
+# Key files
+
+- `src/components`: reusable React components
+- `src/lib`: reusable util code
+- `src/routes`: tanstack file routes
+
+# Guidelines
+
+- ALWAYS use absolute import using `@/`, unless the file is in the same directory.
+- ALWAYS use kebab-case for file names
+- when importing useQuery/useMutation from convex/react, alias them with useConvexQuery/useConvexMutation
+- Do not attempt to create a preview server. There is one running already at port 3001.
+- After create a new file route, run `bunx tsr generate`
+- No testing is in place right now, so skip that for now.