fix(03): login redirect + API internal URL for Docker networking

- Use window.location.href for full page reload after login (ensures auth state)
- Add API_INTERNAL_URL for server-side requests within Docker network
- Remove unnecessary credentials:'include' from SSR fetch calls
- Update planning state for Phase 03 progress

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

.planning/STATE.md

@@ -3,14 +3,14 @@ gsd_state_version: 1.0
 milestone: v1.0
 milestone_name: milestone
 status: executing
-stopped_at: Completed 02-02-PLAN.md
-last_updated: "2026-06-19T10:27:41.286Z"
+stopped_at: context exhaustion at 75% (2026-06-19)
+last_updated: "2026-06-19T12:37:50.398Z"
 last_activity: 2026-06-19 -- Phase 03 execution started
 progress:
   total_phases: 6
   completed_phases: 1
   total_plans: 12
-  completed_plans: 7
+  completed_plans: 10
   percent: 17
 ---
 
@@ -93,6 +93,6 @@ Items acknowledged and carried forward from previous milestone close:
 
 ## Session Continuity
 
-Last session: 2026-06-18T11:41:48.372Z
-Stopped at: Completed 02-02-PLAN.md
+Last session: 2026-06-19T12:37:50.391Z
+Stopped at: context exhaustion at 75% (2026-06-19)
 Resume file: None