Close the clawability backlog with deterministic CLI output and lane lineage

Finish the remaining roadmap work by making direct CLI JSON output deterministic across the non-interactive surface, restoring the degraded-startup MCP test as a real workspace test, and adding branch-lock plus commit-lineage primitives so downstream lane consumers can distinguish superseded worktree commits from canonical lineage.

Constraint: Keep the user-facing config namespace centered on .claw while preserving legacy fallback discovery for compatibility
Constraint: Verification needed to stay clean-room and reproducible from the checked-in workspace alone
Rejected: Leave the output-format contract implied by ad-hoc smoke runs only | too easy for direct CLI regressions to slip back into prose-only output
Rejected: Keep commit provenance as free-form detail text | downstream consumers need structured branch/worktree/supersession metadata
Confidence: medium
Scope-risk: moderate
Directive: Extend the JSON contract through the same direct CLI entrypoints instead of adding one-off serializers on parallel code paths
Tested: python .github/scripts/check_doc_source_of_truth.py
Tested: cd rust && cargo fmt --all --check
Tested: cd rust && cargo test --workspace
Tested: cd rust && cargo clippy -p commands -p tools -p rusty-claude-cli --all-targets --no-deps -- -D warnings
Not-tested: full cargo clippy --workspace --all-targets -- -D warnings still reports unrelated pre-existing runtime lint debt outside this change set

rust/crates/runtime/src/mcp_stdio.rs

@@ -2652,8 +2652,37 @@ mod tests {
         });
     }
 
+    fn write_initialize_disconnect_script() -> PathBuf {
+        let root = temp_dir();
+        fs::create_dir_all(&root).expect("temp dir");
+        let script_path = root.join("initialize-disconnect.py");
+        let script = [
+            "#!/usr/bin/env python3",
+            "import sys",
+            "header = b''",
+            r"while not header.endswith(b'\r\n\r\n'):",
+            "    chunk = sys.stdin.buffer.read(1)",
+            "    if not chunk:",
+            "        raise SystemExit(1)",
+            "    header += chunk",
+            "length = 0",
+            r"for line in header.decode().split('\r\n'):",
+            r"    if line.lower().startswith('content-length:'):",
+            r"        length = int(line.split(':', 1)[1].strip())",
+            "if length:",
+            "    sys.stdin.buffer.read(length)",
+            "raise SystemExit(0)",
+            "",
+        ]
+        .join("\n");
+        fs::write(&script_path, script).expect("write script");
+        let mut permissions = fs::metadata(&script_path).expect("metadata").permissions();
+        permissions.set_mode(0o755);
+        fs::set_permissions(&script_path, permissions).expect("chmod");
+        script_path
+    }
+
     #[test]
-    #[ignore = "flaky: intermittent timing issues in CI, see ROADMAP P2.15"]
     fn manager_discovery_report_keeps_healthy_servers_when_one_server_fails() {
         let runtime = Builder::new_current_thread()
             .enable_all()
@@ -2663,6 +2692,7 @@ mod tests {
             let script_path = write_manager_mcp_server_script();
             let root = script_path.parent().expect("script parent");
             let alpha_log = root.join("alpha.log");
+            let broken_script_path = write_initialize_disconnect_script();
             let servers = BTreeMap::from([
                 (
                     "alpha".to_string(),
@@ -2673,8 +2703,8 @@ mod tests {
                     ScopedMcpServerConfig {
                         scope: ConfigSource::Local,
                         config: McpServerConfig::Stdio(McpStdioServerConfig {
-                            command: "python3".to_string(),
-                            args: vec!["-c".to_string(), "import sys; sys.exit(0)".to_string()],
+                            command: broken_script_path.display().to_string(),
+                            args: Vec::new(),
                             env: BTreeMap::new(),
                             tool_call_timeout_ms: None,
                         }),
@@ -2737,6 +2767,7 @@ mod tests {
 
             manager.shutdown().await.expect("shutdown");
             cleanup_script(&script_path);
+            cleanup_script(&broken_script_path);
         });
     }