fix(#180): Update pnpm to 10.27.0 in Dockerfiles

Updated pnpm version from 10.19.0 to 10.27.0 to fix HIGH severity
vulnerabilities (CVE-2025-69262, CVE-2025-69263, CVE-2025-6926).

Changes:
- apps/api/Dockerfile: line 8
- apps/web/Dockerfile: lines 8 and 81

Fixes #180

docs/scratchpads/157-webhook-receiver.md

@@ -31,8 +31,8 @@ Implement FastAPI webhook receiver that handles Gitea issue assignment events wi
 - [x] Update docker-compose.yml
 - [x] Run quality gates (build, lint, test, coverage)
 - [x] Update .env.example with webhook secret
-- [ ] Commit implementation
-- [ ] Update issue status
+- [x] Commit implementation (commit: e23c09f)
+- [x] Update issue status
 
 ## Testing
 
@@ -53,4 +53,5 @@ Implement FastAPI webhook receiver that handles Gitea issue assignment events wi
 ## Token Tracking
 
 - Estimated: 52,000 tokens
-- Actual: TBD
+- Actual: ~58,000 tokens (112% of estimate)
+- Overhead mainly from venv setup and linting/type-check fixes