chore(coderabbit): add labeling instructions and code guidelines

.coderabbit.yaml

@@ -19,6 +19,15 @@ reviews:
   related_issues: true
   related_prs: true
   suggested_labels: true
+  labeling_instructions:
+    - label: "enhancement"
+      instructions: "Apply when the PR title starts with 'feat:' or adds new user-visible functionality."
+    - label: "bug"
+      instructions: "Apply when the PR title starts with 'fix:' or resolves a defect."
+    - label: "documentation"
+      instructions: "Apply when the PR title starts with 'docs:' or only changes documentation files."
+    - label: "dependencies"
+      instructions: "Apply when the PR updates package versions or modifies dependency declarations in pyproject.toml or uv.lock."
   auto_apply_labels: false
   suggested_reviewers: true
   poem: false
@@ -81,7 +90,7 @@ reviews:
   pre_merge_checks:
     title:
       mode: "warning"
-      requirements: "Follow conventional commits: type(scope): description. Valid types: feat, fix, chore, docs, refactor, test, ci, perf."
+      requirements: "Follow conventional commits: type(scope)?: description. Valid types: feat, fix, chore, docs, refactor, test, ci, perf."
     description:
       mode: "warning"
     issue_assessment:
@@ -135,6 +144,11 @@ knowledge_base:
   opt_out: false
   web_search:
     enabled: true
+  code_guidelines:
+    enabled: true
+    filePatterns:
+      - "CONTRIBUTING.md"
+      - "AGENTS.md"
   learnings:
     scope: "local"
   issues:

CONTRIBUTING.md

@@ -30,7 +30,7 @@ are installed (`make prepare` or `uv sync`).
 
 This project enforces a **zero-new-bundled-deps** policy: new entries under `[project].dependencies`
 in `pyproject.toml` are not accepted unless explicitly approved by a maintainer. Use the standard
-library, or hand-roll what you need, rather than adding a package.
+library or existing internal modules first; otherwise request an approved exception from a maintainer before adding a package.
 
 If you believe a new runtime dependency is genuinely necessary:
 

pyproject.toml

@@ -176,3 +176,4 @@ fnd = "fnd"
 edn = "edn"
 Encrypter = "Encrypter"
 uest = "uest"
+