fix: détection externe — champ detect (sonde PATH explicite) pour les lanceurs interpréteurs

lazycodex (run: npx lazycodex-ai) et nanobot (run: python -m nanobot)
étaient déclarés « external » dès que npx/python étaient sur le PATH :
la sonde utilisait le premier mot de run au lieu du vrai binaire.

- AgentDef.detect : sonde PATH explicite, repli sur first_token sinon
- probe.rs : cache invalidé quand les tokens du catalogue changent
  (token_hash), plus besoin d'attendre un changement de PATH
- config.yaml : detect: lazycodex-ai / detect: nanobot
- tests : detect_token_prefers_explicit_binary + 432 tests verts
- v1.0.3, man pages régénérées

src/config.rs

@@ -398,6 +398,13 @@ pub struct AgentDef {
     /// Command used to start the agent (e.g. "claude", "python -m nanobot").
     #[serde(default)]
     pub run: Option<String>,
+    /// Binary name probed on the PATH for external detection. When unset,
+    /// the first token of `run` is used — which is wrong for interpreter
+    /// launchers ("npx pkg", "python -m pkg"): the interpreter itself would
+    /// be matched, reporting the agent as present whenever node/python is
+    /// on the PATH. Set it to the real entry point (e.g. "lazycodex-ai").
+    #[serde(default)]
+    pub detect: Option<String>,
     /// Default arguments appended to the run command.
     #[serde(default)]
     pub args: Vec<String>,
@@ -516,6 +523,12 @@ impl AgentDef {
             })
     }
 
+    /// Binary probed on the PATH for external detection: the explicit
+    /// `detect` name when set, otherwise the first token of `run`.
+    pub fn detect_token(&self) -> Option<String> {
+        self.detect.clone().or_else(|| self.first_token())
+    }
+
     /// The run command split into tokens (empty when unset).
     pub fn run_tokens(&self) -> Vec<String> {
         self.run
@@ -1167,6 +1180,31 @@ mod tests {
         assert!(validate(&cfg).is_empty(), "embedded config invalid: {:?}", validate(&cfg));
     }
 
+    #[test]
+    fn detect_token_prefers_explicit_binary() {
+        // Interpreter launcher: without `detect`, the interpreter itself
+        // would be probed (false "external" when node/python is on PATH).
+        let a: AgentDef = serde_yaml::from_str(
+            "name: lazycodex\nrun: \"npx lazycodex-ai\"\ndetect: lazycodex-ai\n",
+        )
+        .unwrap();
+        assert_eq!(a.detect_token().as_deref(), Some("lazycodex-ai"));
+        // No `detect`: falls back to the first token of run.
+        let b: AgentDef =
+            serde_yaml::from_str("name: nanobot\nrun: \"python -m nanobot\"\n").unwrap();
+        assert_eq!(b.detect_token().as_deref(), Some("python"));
+        assert_eq!(b.first_token().as_deref(), Some("python"));
+        // Plain binary command is unchanged.
+        let c: AgentDef = serde_yaml::from_str("name: claude\nrun: claude\n").unwrap();
+        assert_eq!(c.detect_token().as_deref(), Some("claude"));
+        // The embedded catalog must stay valid with the new field.
+        let cfg: Config = serde_yaml::from_str(DEFAULT_CONFIG).unwrap();
+        let lazy = cfg.agents.iter().find(|a| a.name == "lazycodex").unwrap();
+        assert_eq!(lazy.detect_token().as_deref(), Some("lazycodex-ai"));
+        let nano = cfg.agents.iter().find(|a| a.name == "nanobot").unwrap();
+        assert_eq!(nano.detect_token().as_deref(), Some("nanobot"));
+    }
+
     #[test]
     fn expands_paths() {
         std::env::set_var("AM_TEST_EXPAND_VAR", "expanded-value");