feat(phase3): add scripts, diagrams, and lint integration

- scripts/tag.sh: CalVer validation + dual-remote push
- scripts/changelog.sh: prepend release entry to CHANGELOG
- scripts/lint-public.sh: public IP, .env, and setup file checks
- sync.sh: run lint before push
- public/assets/: Mermaid diagrams for network topology, DNS chain, auth flow
- CLAUDE.md: update current phase to Phase 3

assets/network-topology.md

@@ -0,0 +1,15 @@
+# Network Topology
+
+```mermaid
+graph TD
+  ONT[AT&T Fiber ONT] --> BGW[BGW320 IP Passthrough]
+  BGW --> PF[pfSense N100]
+  PF --> SW[Omada Switch]
+  SW --> MGMT[VLAN 1000 MGMT\n10.0.0.0/24]
+  SW --> LAN[VLAN 1010 LAN\n10.1.0.0/24]
+  SW --> HL[VLAN 1020 Homelab\n10.2.0.0/24]
+  SW --> GUEST[VLAN 1030 Guests\n10.3.0.0/24]
+  SW --> IOT[VLAN 1040 IoT\n10.4.0.0/24]
+  SW --> WFH[VLAN 1050 WFH\n10.5.0.0/24]
+  SW --> DMZ[VLAN 1 DMZ\n10.99.0.0/24]
+```