chore: move agent routing to OpenCode Go; add firstmate tooling

- crew-dispatch.json: route crew tasks to OpenCode Go models
- opencode/opencode2: pin opencode-go/gpt-6-luna
- grok: default to grok-4.5 with high reasoning, permission auto
- home.nix: axiTools activation for the *-axi CLIs; crewmate harness
  opencode; no-mistakes agent list opencode-only

home/.grok/config.toml

@@ -7,7 +7,8 @@ name = "xAI Official"
 git = "https://github.com/xai-org/plugin-marketplace.git"
 
 [models]
-default = "qwen"
+default = "grok-4.5"
+default_reasoning_effort = "high"
 
 [model.qwen]
 model = "Jundot/Qwen3.6-35B-A3B-oQ4-mtp"
@@ -24,7 +25,7 @@ max_completion_tokens = 65536
 theme = "rosepine"
 max_thoughts_width = 120
 fork_secondary_model = "grok-build"
-permission_mode = "always-approve"
+permission_mode = "auto"
 yolo = false
 compact_mode = false
 
@@ -32,4 +33,4 @@ compact_mode = false
 installer = "internal"
 
 [privacy]
-privacy_banner_acked = "2026-09-21T16:02:21Z"
+privacy_banner_acked = "2026-09-24T02:33:29Z"