test(infra): isolate DATA_DIR per test process; raise Stryker concurrency 1→4 (#4078)

* test(infra): isolate DATA_DIR per test process; raise Stryker concurrency 1→4

Every test process resolved DATA_DIR to the same default (~/.omniroute) when the env
var was unset (src/lib/dataPaths.ts::resolveDataDir), so concurrent test files opened
the SAME on-disk storage.sqlite. node:test spawns a process per file and Stryker spawns
one per sandbox, so this shared file caused cross-file state races:
- SQLite lock contention that hung `npm run test:unit` under high --test-concurrency
  (the ~95-min local hang), and
- the non-deterministic baseline that forced stryker.conf.json to concurrency: 1, which
  in turn could not finish the ~15k-mutant run inside the nightly timeout (the cancelled
  2026-06-16/17 nightly-mutation runs) — blocking Quality Gate v2 / Fase 9 Onda 2.

open-sse/utils/setupPolyfill.ts could NOT host the fix: it is imported by production
(bin/omniroute.mjs, proxyFetch.ts, proxyDispatcher.ts), where redirecting DATA_DIR would
point the live SQLite DB at a throwaway temp dir. So this adds a TEST-ONLY
tests/_setup/isolateDataDir.ts that gives each process its own temp DATA_DIR when none is
set (tests that set DATA_DIR explicitly still win), wired via --import into the test,
mutation and CI invocations.

Verified:
- Stryker dry-run A/B at concurrency=4: FAILS without the isolation import
  (account-fallback-service tap exit 9, a cross-file race) and PASSES with it.
- Full `npm run test:unit` green with isolation (0 fail; a one-off
  chatcore-translation-paths timeout flake did not reproduce and passes 3/3 isolated)
  and noticeably faster — the DB lock contention is gone.
- New tests/unit/isolate-datadir.test.ts guards the contract (unique temp DATA_DIR when
  unset; explicit DATA_DIR respected).

Wired the --import into: package.json (13 test scripts), stryker.conf.json (tap.nodeArgs
+ concurrency 1→4), .github/workflows/quality.yml (TIA step), ci.yml (the 5
unit/coverage/integration commands), and bumped nightly-mutation.yml timeout 120→180 for
the first cold run before the incremental cache is seeded.

* ci(quality): run the TIA gate at CI concurrency (4) to stop oversubscription flakes

The TIA "Impacted unit tests" step (made blocking in #4069) ran its fail-safe via
`npm run test:unit` — concurrency=20, tuned for multi-core dev machines. On a 4-vCPU CI
runner that is 5x oversubscribed, so timing-sensitive tests flake under the load (e.g.
`db-backup-extended` "The database connection is not open", `chatcore-translation-paths`
upstream-timeout). That intermittently fails a blocking gate on legitimate PRs — exactly
what surfaced on the DATA_DIR-isolation PR, whose package.json/workflow changes trip the
__RUN_ALL__ fail-safe.

Run both the impacted set and the fail-safe at --test-concurrency=4, matching the stable
ci.yml unit job. Adds a `test:unit:ci` script (test:unit at concurrency=4). The DATA_DIR
isolation in this PR keeps the parallel run race-free, so the only change here is matching
the runner's core count. Verified locally: db-backup-extended passes 8/8 in isolation
(5 with isolation, 3 without).

.github/workflows/ci.yml

@@ -513,7 +513,7 @@ jobs:
           cache: npm
       - run: npm ci
       - run: npm run check:node-runtime
-      - run: node --max-old-space-size=4096 --import tsx --test --test-force-exit --test-concurrency=4 --test-shard=${{ matrix.shard }}/8 tests/unit/*.test.ts "tests/unit/{api,auth,authz,build,cli,cli-helper,compression,correctness,cors,dashboard,db,db-adapters,docs,gamification,guardrails,lib,mcp,runtime,security,services,settings,shared,ui}/**/*.test.ts"
+      - run: node --max-old-space-size=4096 --import tsx --import ./tests/_setup/isolateDataDir.ts --test --test-force-exit --test-concurrency=4 --test-shard=${{ matrix.shard }}/8 tests/unit/*.test.ts "tests/unit/{api,auth,authz,build,cli,cli-helper,compression,correctness,cors,dashboard,db,db-adapters,docs,gamification,guardrails,lib,mcp,runtime,security,services,settings,shared,ui}/**/*.test.ts"
 
   test-vitest:
     name: Vitest (MCP / autoCombo / UI components)
@@ -566,7 +566,7 @@ jobs:
       - run: npm ci
       - run: npm run check:node-runtime
       - run: npm run build
-      - run: node --import tsx --test --test-force-exit --test-concurrency=4 --test-shard=${{ matrix.shard }}/2 tests/unit/*.test.ts "tests/unit/{api,auth,authz,build,cli,cli-helper,compression,correctness,cors,dashboard,db,db-adapters,docs,gamification,guardrails,lib,mcp,runtime,security,services,settings,shared,ui}/**/*.test.ts"
+      - run: node --import tsx --import ./tests/_setup/isolateDataDir.ts --test --test-force-exit --test-concurrency=4 --test-shard=${{ matrix.shard }}/2 tests/unit/*.test.ts "tests/unit/{api,auth,authz,build,cli,cli-helper,compression,correctness,cors,dashboard,db,db-adapters,docs,gamification,guardrails,lib,mcp,runtime,security,services,settings,shared,ui}/**/*.test.ts"
 
   node-26-compat:
     name: Node 26 Compatibility (${{ matrix.shard }}/2)
@@ -592,7 +592,7 @@ jobs:
       - run: npm ci
       - run: npm run check:node-runtime
       - run: npm run build
-      - run: node --import tsx --test --test-force-exit --test-concurrency=4 --test-shard=${{ matrix.shard }}/2 tests/unit/*.test.ts "tests/unit/{api,auth,authz,build,cli,cli-helper,compression,correctness,cors,dashboard,db,db-adapters,docs,gamification,guardrails,lib,mcp,runtime,security,services,settings,shared,ui}/**/*.test.ts"
+      - run: node --import tsx --import ./tests/_setup/isolateDataDir.ts --test --test-force-exit --test-concurrency=4 --test-shard=${{ matrix.shard }}/2 tests/unit/*.test.ts "tests/unit/{api,auth,authz,build,cli,cli-helper,compression,correctness,cors,dashboard,db,db-adapters,docs,gamification,guardrails,lib,mcp,runtime,security,services,settings,shared,ui}/**/*.test.ts"
 
   test-coverage-shard:
     name: Coverage Shard (${{ matrix.shard }}/8)
@@ -632,7 +632,7 @@ jobs:
             --reporter=json \
             --exclude=tests/** \
             --exclude=**/*.test.* \
-            node --max-old-space-size=4096 --import tsx --test --test-force-exit --test-concurrency=4 \
+            node --max-old-space-size=4096 --import tsx --import ./tests/_setup/isolateDataDir.ts --test --test-force-exit --test-concurrency=4 \
               --test-shard=${{ matrix.shard }}/8 tests/unit/*.test.ts "tests/unit/{api,auth,authz,build,cli,cli-helper,compression,correctness,cors,dashboard,db,db-adapters,docs,gamification,guardrails,lib,mcp,runtime,security,services,settings,shared,ui}/**/*.test.ts"
       - name: Upload raw shard coverage
         if: always()
@@ -902,7 +902,7 @@ jobs:
           cache: npm
       - run: npm ci
       - run: npm run check:node-runtime
-      - run: node --import tsx --test --test-force-exit --test-concurrency=1 --test-shard=${{ matrix.shard }}/2 tests/integration/*.test.ts
+      - run: node --import tsx --import ./tests/_setup/isolateDataDir.ts --test --test-force-exit --test-concurrency=1 --test-shard=${{ matrix.shard }}/2 tests/integration/*.test.ts
 
   test-security:
     name: Security Tests

.github/workflows/nightly-mutation.yml

@@ -11,11 +11,16 @@ jobs:
   stryker:
     name: Stryker mutation testing (8 critical modules — advisory)
     runs-on: ubuntu-latest
-    # Mutation testing is expensive (~200-500 mutants, 30-90 min). It runs only
+    # Mutation testing is expensive (~15k mutants across 8 modules). It runs only
     # on the nightly schedule / manual dispatch, never on PRs. The score is NOT
     # yet enforced as a ratchet (wired in a later INT phase) — for now the job
     # just produces the HTML/JSON report and uploads it as an artifact.
-    timeout-minutes: 120
+    #
+    # Runs at stryker concurrency=4 (was 1) now that ./tests/_setup/isolateDataDir.ts
+    # gives each test process its own DATA_DIR — at concurrency=1 the full phase did
+    # not finish inside the timeout (the cancelled 2026-06-16/17 runs). 180 min leaves
+    # headroom for the first cold run before the incremental cache is seeded.
+    timeout-minutes: 180
     steps:
       - uses: actions/checkout@v6
         with:

.github/workflows/quality.yml

@@ -71,9 +71,14 @@ jobs:
           node scripts/quality/build-test-impact-map.mjs
           SEL="$(node scripts/quality/select-impacted-tests.mjs)"
           if [ -z "$SEL" ]; then echo "No source/test changes — skipping unit tests"; exit 0; fi
+          # CI runners are 4-vCPU; run at --test-concurrency=4 (matching the ci.yml unit
+          # job) rather than test:unit's local-tuned concurrency=20. Oversubscribing the
+          # runner makes timing-sensitive tests (db-backup, upstream-timeout, ...) flake,
+          # which must not happen on a blocking gate. DATA_DIR isolation keeps the parallel
+          # run race-free regardless of concurrency.
           if echo "$SEL" | grep -q "__RUN_ALL__"; then
-            echo "Fail-safe: running FULL unit suite"; npm run test:unit; exit $?
+            echo "Fail-safe: running FULL unit suite (CI concurrency)"; npm run test:unit:ci; exit $?
           fi
           echo "Running impacted tests:"; echo "$SEL"
           mapfile -t FILES <<< "$SEL"
-          node --import tsx --import ./open-sse/utils/setupPolyfill.ts --test --test-force-exit --test-concurrency=8 "${FILES[@]}"
+          node --import tsx --import ./open-sse/utils/setupPolyfill.ts --import ./tests/_setup/isolateDataDir.ts --test --test-force-exit --test-concurrency=4 "${FILES[@]}"