fix(disk-cleanup): restrict cron-output classification to output subtree

plugins/disk-cleanup/disk_cleanup.py

@@ -481,7 +481,12 @@ def guess_category(path: Path) -> Optional[str]:
         }:
             return None
         if top == "cron" or top == "cronjobs":
-            return "cron-output"
+            # Only the per-run artefact subtree is disposable. Top-level
+            # files like jobs.json (the durable scheduler registry) and
+            # .tick.lock must never be auto-tracked for cleanup.
+            if len(rel.parts) >= 2 and rel.parts[1] == "output":
+                return "cron-output"
+            return None
         if top == "cache":
             return "temp"
     except ValueError:

tests/plugins/test_disk_cleanup_plugin.py

@@ -127,13 +127,41 @@ def test_skips_protected_top_level(self, _isolate_env):
         # Even though it matches test_* pattern, logs/ is excluded.
         assert dg.guess_category(p) is None
 
-    def test_cron_subtree_categorised(self, _isolate_env):
+    def test_cron_output_subtree_categorised(self, _isolate_env):
+        dg = _load_lib()
+        run_dir = _isolate_env / "cron" / "output" / "job-123"
+        run_dir.mkdir(parents=True)
+        p = run_dir / "run.md"
+        p.write_text("x")
+        assert dg.guess_category(p) == "cron-output"
+
+    def test_cron_jobs_registry_not_categorised(self, _isolate_env):
+        """Regression: ~/.hermes/cron/jobs.json is the durable scheduler
+        registry and must never be auto-tracked as cleanup candidate."""
+        dg = _load_lib()
+        cron_dir = _isolate_env / "cron"
+        cron_dir.mkdir()
+        p = cron_dir / "jobs.json"
+        p.write_text("[]")
+        assert dg.guess_category(p) is None
+
+    def test_cron_tick_lock_not_categorised(self, _isolate_env):
+        """Regression: the scheduler's tick lock is control-plane state."""
+        dg = _load_lib()
+        cron_dir = _isolate_env / "cron"
+        cron_dir.mkdir()
+        p = cron_dir / ".tick.lock"
+        p.write_text("")
+        assert dg.guess_category(p) is None
+
+    def test_cron_top_level_file_not_categorised(self, _isolate_env):
+        """Any other top-level cron/ file should also be left alone."""
         dg = _load_lib()
         cron_dir = _isolate_env / "cron"
         cron_dir.mkdir()
         p = cron_dir / "job_output.md"
         p.write_text("x")
-        assert dg.guess_category(p) == "cron-output"
+        assert dg.guess_category(p) is None
 
     def test_ordinary_file_returns_none(self, _isolate_env):
         dg = _load_lib()