ci: add coverage gates (backend pytest-cov + frontend vitest thresholds)

Backend: pytest-cov with --cov-fail-under=40 ratchet (currently 43%; drag is
the untested Flask API + network-heavy llm/swarm_runner). Frontend: vitest v8
coverage thresholds (stmts 65 / lines 68 / branches 55 / funcs 50) over the
unit-tested surface — Result.vue excluded (unmountable; its helpers are
mirror-tested in ResultHelpers.test.js). Both wired into CI + ci-local.

Also corrected tech_debt: utils/retry.py is NOT dead (imported by utils/llm.py).

Author: Harsh Patadia

.github/workflows/ci.yml

@@ -65,8 +65,8 @@ jobs:
       - name: Lint (eslint)
         run: npm run lint
 
-      - name: Tests
-        run: npm run test:run
+      - name: Tests + coverage
+        run: npm run coverage
 
       - name: Build
         run: npm run build

backend/pyproject.toml

@@ -33,6 +33,7 @@ dependencies = [
 dev = [
     "pytest>=8.0.0",
     "pytest-asyncio>=0.23.0",
+    "pytest-cov>=5.0.0",
     "pipreqs>=0.5.0",
 ]
 
@@ -44,8 +45,13 @@ build-backend = "hatchling.build"
 dev = [
     "pytest>=8.0.0",
     "pytest-asyncio>=0.23.0",
+    "pytest-cov>=5.0.0",
 ]
 
+[tool.pytest.ini_options]
+# Coverage is a ratchet floor (current ~43%): prevents regression, raise over time.
+addopts = "--cov=app --cov-report=term-missing --cov-fail-under=40"
+
 [tool.hatch.build.targets.wheel]
 packages = ["app"]