fix(ci): update unit-test workflow paths to match current source layout

Replace stale pkg/** filter with src/langbot/** and add uv.lock.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

.github/workflows/run-tests.yml

@@ -4,20 +4,22 @@ on:
   pull_request:
     types: [opened, ready_for_review, synchronize]
     paths:
-      - 'pkg/**'
+      - 'src/langbot/**'
       - 'tests/**'
       - '.github/workflows/run-tests.yml'
       - 'pyproject.toml'
+      - 'uv.lock'
       - 'run_tests.sh'
   push:
     branches:
       - master
       - develop
     paths:
-      - 'pkg/**'
+      - 'src/langbot/**'
       - 'tests/**'
       - '.github/workflows/run-tests.yml'
       - 'pyproject.toml'
+      - 'uv.lock'
       - 'run_tests.sh'
 
 jobs: