[GEMINI-HARDEN-01] Replace hard-coded fleet inventory with repo-native config

Add fleet.inventory and fleet.path_contracts to config.yaml:
- Central source of truth for IPs, ports, roles, remote paths
- Introduce get_config_path(), load_fleet_inventory(), get_path_contract()
- Updated fleet_llama.py, self_healing.py, telemetry.py, agent_dispatch.py,
  skill_installer.py to read from config instead of hard-coded dicts/paths
- Documented inventory contract and override mechanism in scripts/README.md

Scripts retain forward-compatible fallback defaults for backwards compatibility.

Closes #433

config.yaml

@@ -7,6 +7,37 @@ agent:
   max_turns: 30
   reasoning_effort: medium
   verbose: false
+fleet:
+  inventory:
+    mac:
+      ip: 10.1.10.77
+      port: 8080
+      role: hub
+      remote_root: /opt/hermes
+      capabilities: [gateway, orchestrator]
+    ezra:
+      ip: 143.198.27.163
+      port: 8080
+      role: forge
+      remote_root: /opt/hermes
+      capabilities: [forge, agent-host]
+    allegro:
+      ip: 167.99.126.228
+      port: 8080
+      role: agent-host
+      remote_root: /opt/hermes
+      capabilities: [agent-host, llm-host]
+    bezalel:
+      ip: 159.203.146.185
+      port: 8080
+      role: world-host
+      remote_root: /opt/hermes
+      capabilities: [world-host, llm-host]
+  path_contracts:
+    hermes_agent_local: ../hermes-agent
+    hermes_remote: /opt/hermes
+    skills_remote: /opt/hermes/skills
+
 terminal:
   backend: local
   cwd: .