Fix project templates structure and application

[jaeyunha]

Summary

• add structured project template settings for defaults, milestones, starter issues, metadata, and archive state
• add edit/delete/archive/duplicate-capable project template UI and PATCH/DELETE API routes
• expose templates in the new project flow and apply defaults/child records atomically on project creation

Validation

• make check
• npm test -- project-template-settings project-templates-route projects-route project-templates-view projects-list
• make test-e2e (baseline/env failures: 72 passed, 11 failed, 4 flaky; failures in existing auth/canonical/sidebar/team route specs, not template-specific)
• make test (terminated by harness after ~2m with no failing output)
• API manual attempted on dev server at localhost:3001; /api/test/create-session unavailable outside test server returned {"error":"Not found"}, subsequent protected API requests redirected to /login