feat: add carpenter walkthrough release gate (hydration, readiness, material link review)

Implements the plan from the carpenter walkthrough audit: make the
project flow -> final review -> PDF path measurable and safe to gate
CI on.

- projectHydrationService loads a project's geometry/labor/materials/
  rentals/packages/calculation in parallel and reports per-resource
  timing plus the slowest resource, so hydration SLA breaches are
  visible instead of silent
- projectReadiness centralizes the blocking checks final review must
  pass before a quote can be sent (name, customer, description,
  materials/labor present, zero-price lines)
- pdfSourceSignature detects when a generated PDF is stale relative to
  the current project data, so a carpenter doesn't send an outdated
  quote
- MaterialLinkReview + new customer-projects match-preview/link
  endpoints let a user review and confirm suggested master-material
  matches instead of silently auto-linking
- ProjectFlow refactored around the new hydration/readiness utilities;
  FinalReview surfaces readiness checks and unlinked material counts
- CI: the carpenter smoke test (full-roof-quote-flow.spec.js) is now
  a blocking gate on main, with the rest of the Playwright suite
  running best-effort alongside it
- docs/qa/CARPENTER_WALKTHROUGH_RELEASE_GATE.md documents the gate and
  the monthly production audit procedure

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

docs/qa/CARPENTER_WALKTHROUGH_RELEASE_GATE.md

@@ -0,0 +1,43 @@
+# Carpenter Walkthrough Release Gate
+
+## Blocking CI gate
+
+Every pull request to `main` runs `tests/full-roof-quote-flow.spec.js` as a blocking Playwright smoke test against the CI server. It verifies app login, supported roof types, geometry calculation and the core pricing basis.
+
+The remaining Playwright suite is still best-effort while legacy scenarios are stabilized. Artifact upload is always best-effort and must not decide CI status.
+
+## Monthly production audit
+
+Run `tests/monthly-carpenter-audit.spec.js` against the production-like target with a known audit project:
+
+```bash
+cd tests
+PLAYWRIGHT_BASE_URL=https://tilbudsgiveren.alw.dk \
+PLAYWRIGHT_USERNAME="$PLAYWRIGHT_USERNAME" \
+PLAYWRIGHT_PASSWORD="$PLAYWRIGHT_PASSWORD" \
+AUDIT_PROJECT_ID=392 \
+CARPENTER_HYDRATION_SLA_MS=5000 \
+npx playwright test monthly-carpenter-audit.spec.js --project=chromium --reporter=list
+```
+
+The audit fails when:
+
+- project hydration exceeds the explicit SLA
+- ProjectFlow and Final Review disagree about unlinked material count
+- controlled quote total changes unexpectedly
+- a newly generated PDF is stale, invalid or longer than three pages
+- the browser observes API 5xx responses or console errors
+- the mobile page has horizontal overflow
+
+Do not use the monthly audit as an automated production write from CI. Run it deliberately with the designated audit project after deploy and during the monthly carpenter review.
+
+## Release evidence
+
+Record:
+
+- commit and environment
+- hydration duration
+- PDF page count
+- API/console failures
+- readiness/material-link count
+- screenshot/video paths when a gate fails