infra(04-00): route /c/ → /client/, Dockerfile, Gitea deploy

- Rename src/app/c/[token] → src/app/client/[token]
- Update proxy.ts, ClientRow, admin client detail with /client/ path
- Add output: "standalone" to next.config.ts for Docker build
- Add Dockerfile (multi-stage, node:20-alpine) and .dockerignore
- Push schema to Coolify Postgres via SSH tunnel (drizzle-kit push ✓)
- Update CLAUDE.md constraint 4 to reflect /client/ route
- Add Phase 4 planning artifacts (04-00, 04-RESEARCH, 04-PATTERNS)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.planning/STATE.md

@@ -4,14 +4,14 @@ milestone: v1.0
 milestone_name: milestone
 status: executing
 stopped_at: Phase 1 execution complete — all 5 plans done, E2E verified (valid token 200, invalid 404)
-last_updated: "2026-05-19T21:12:54.673Z"
-last_activity: 2026-05-19
+last_updated: "2026-05-21T11:56:14.461Z"
+last_activity: 2026-05-21 -- Phase 4 planning complete
 progress:
-  total_phases: 4
+  total_phases: 5
   completed_phases: 3
-  total_plans: 13
+  total_plans: 17
   completed_plans: 13
-  percent: 100
+  percent: 76
 ---
 
 # Project State
@@ -27,8 +27,8 @@ See: .planning/PROJECT.md (updated 2026-05-09)
 
 Phase: 4
 Plan: Not started
-Status: Executing Phase 03
-Last activity: 2026-05-19
+Status: Ready to execute
+Last activity: 2026-05-21 -- Phase 4 planning complete
 
 Progress: [██░░░░░░░░] 25%