chore(phase-3): mark on-prem license validation complete

Phase 3 work was done in TapTrack on-prem repo.
Hub side (POST /api/licenses/validate) was already done in Phase 1.

PAUL updates:
- ROADMAP: Phase 3 marked complete
- STATE: Phase 3 done, Phase 4 next
- phases/03-onprem-license/README.md: updated with what was built

.paul/STATE.md

@@ -3,10 +3,10 @@
 ## Current Position
 
 Milestone: v1.0 — Foundation & Core Services
-Phase: 2 of 15 (School Registry + License Management — complete)
-Plan: Phase 2 complete — Phase 3 next
-Status: **Phase 2 applied — ready to begin Phase 3**
-Last activity: 2026-03-15 — Phase 2 complete (school create/edit modal, license editor, activate/suspend, subscription plan, SMS credit top-up, ledger)
+Phase: 3 of 15 (On-Prem License Validation — complete)
+Plan: Phase 3 complete — Phase 4 next
+Status: **Phase 3 applied — ready to begin Phase 4**
+Last activity: 2026-03-15 — Phase 3 complete (TapTrack on-prem: license validation task, startup check, hub router, frontend warning banner)
 
 ## Loop Position
 
@@ -21,7 +21,7 @@ PLAN ──▶ APPLY ──▶ UNIFY
 
 - Phase 1  (Project Setup & Infrastructure): [██████████] 100% ✓
 - Phase 2  (School Registry + License Mgmt): [██████████] 100% ✓
-- Phase 3  (On-Prem License Validation):     [░░░░░░░░░░]   0%
+- Phase 3  (On-Prem License Validation):     [██████████] 100% ✓
 - Phase 4  (SMS Gateway):                    [░░░░░░░░░░]   0%
 - Phase 5  (On-Prem SMS Polling Agent):      [░░░░░░░░░░]   0%
 - Phase 6  (Super Admin Dashboard UI):       [░░░░░░░░░░]   0%
@@ -37,8 +37,8 @@ PLAN ──▶ APPLY ──▶ UNIFY
 
 ## Next Action
 
-Run: `/paul:plan` for Phase 3 — On-Prem License Validation
-Resume file: .paul/ROADMAP.md → Phase 3
+Run: `/paul:plan` for Phase 4 — SMS Gateway (credits + queue)
+Resume file: .paul/ROADMAP.md → Phase 4
 
 ## Repo