fix(gateway): persist pairing tokens and honor docker config (#630)

* fix(gateway): honor config bind settings and persist pairing

Resolve docker-compose startup and restart friction by:
- using config host/port defaults for gateway/daemon unless CLI flags are passed
- persisting paired token hashes to config.toml on successful /pair
- running container default command as 'zeroclaw gateway' (no hardcoded --host/--port overrides)
- updating compose image/docs to zeroclaw-labs namespace
- adding MODEL env fallback for default_model override and targeted regression tests

* chore(ci): sync lockfile and restore rustfmt parity

Update Cargo.lock to match Cargo.toml and format src/service/mod.rs so rust quality gates stop failing with unrelated baseline drift.

src/config/schema.rs

@@ -2003,8 +2003,8 @@ impl Config {
             }
         }
 
-        // Model: ZEROCLAW_MODEL
-        if let Ok(model) = std::env::var("ZEROCLAW_MODEL") {
+        // Model: ZEROCLAW_MODEL or MODEL
+        if let Ok(model) = std::env::var("ZEROCLAW_MODEL").or_else(|_| std::env::var("MODEL")) {
             if !model.is_empty() {
                 self.default_model = Some(model);
             }
@@ -3292,6 +3292,22 @@ default_temperature = 0.7
         std::env::remove_var("ZEROCLAW_MODEL");
     }
 
+    #[test]
+    fn env_override_model_fallback() {
+        let _env_guard = env_override_test_guard();
+        let mut config = Config::default();
+
+        std::env::remove_var("ZEROCLAW_MODEL");
+        std::env::set_var("MODEL", "anthropic/claude-3.5-sonnet");
+        config.apply_env_overrides();
+        assert_eq!(
+            config.default_model.as_deref(),
+            Some("anthropic/claude-3.5-sonnet")
+        );
+
+        std::env::remove_var("MODEL");
+    }
+
     #[test]
     fn env_override_workspace() {
         let _env_guard = env_override_test_guard();