fix(TASK-046): engine polish + wizard bypass + ETXTBSY retry

- unify hook base-env assembly on hooks::base_envs_parts (drop the
  hand-copied hook_base_envs in function/agents.rs; graph executor and
  spawn-result hooks now share the single construction site, test-pinned)
- factor the duplicated job.started dispatch in jobs.rs handle_start
  into one fire_job_started helper
- COYOTE_LLM_ERROR now carries the immediate error (to_string()),
  matching COYOTE_TOOL_ERROR; test pins the new format
- remove all stale #[allow(dead_code)] markers in src/hooks.rs
- test infra: rename install_warn_collector -> install_log_collector,
  add poison-symmetric warn_snapshot/debug_snapshot helpers, hoist a
  shared EnvVarGuard (TestConfigDirGuard now builds on it), add a
  same-fire payload-uniqueness test, and give global_tools env
  overrides the same malformed-JSON debug diagnostic as global_hooks
- inspection-only flags (--info et al) bypass the first-run wizard:
  missing config + info_flag returns Config::default() without writing
  anything, in both the sandbox and interactive arms (tests included)
- bound the shim-relocation test's exec in an ETXTBSY retry (10x50ms)
- document the intended 'roles' reserved-name asymmetry at
  resolve_bundle_name's gate

src/function/mod.rs

@@ -4795,6 +4795,27 @@ mod tests {
     fn built_shims_resolve_paths_at_runtime_after_relocation() {
         use std::os::unix::fs::PermissionsExt;
 
+        // A shim written moments ago can still be open for writing somewhere
+        // in the process (schedule-dependent), making exec fail with
+        // ETXTBSY; retry briefly instead of flaking.
+        fn output_with_etxtbsy_retry(
+            command: &mut process::Command,
+        ) -> std::io::Result<process::Output> {
+            let mut attempts = 0;
+            loop {
+                match command.output() {
+                    Err(err)
+                        if err.kind() == std::io::ErrorKind::ExecutableFileBusy
+                            && attempts < 10 =>
+                    {
+                        attempts += 1;
+                        std::thread::sleep(Duration::from_millis(50));
+                    }
+                    ret => return ret,
+                }
+            }
+        }
+
         let root = temp_file("-shim-relocate-", "");
         let home_a = root.join("home-a");
         let config_a = home_a.join("coyote");
@@ -4858,14 +4879,14 @@ mod tests {
             return;
         }
 
-        let output = process::Command::new(&moved_shim)
+        let mut command = process::Command::new(&moved_shim);
+        command
             .arg("{}")
             .env_remove(&config_env)
             .env_remove(&functions_env)
             .env_remove("LLM_OUTPUT")
-            .env_remove("LLM_TOOL_DATA_FILE")
-            .output()
-            .unwrap();
+            .env_remove("LLM_TOOL_DATA_FILE");
+        let output = output_with_etxtbsy_retry(&mut command).unwrap();
         let stdout = String::from_utf8_lossy(&output.stdout);
         assert!(
             output.status.success(),