fix: frame the remaining JSONL readers on LF

#5117 fixed four readers of the per-Goal run index. The same framing defect
exists in nine more places that parse one JSON document per line after
`read_text(...).splitlines()`:

- `chat_store.py` (stored chat rows)
- `doctor.py` (installation index)
- `domain_state.py` (domain state rows)
- `event_sourced_state.py` (the append-only event log)
- `domain_packs/issue_fix.py` (two readers)
- `capabilities/explore/result_log.py` (three readers)

All of these files also write with `json.dumps(..., ensure_ascii=False)`, which
leaves U+0085/U+2028/U+2029 in a value verbatim, and `str.splitlines()` treats
them as line breaks: one record becomes two fragments, `json.loads` fails on
both, and the row is dropped or reported as invalid. Frame on LF instead.

Validation: a new case in `tests/test_event_sourced_state_store.py` writes one
event whose title carries U+0085 and asserts it round-trips; it raises
`StateEventError` before the change and passes after. The other eight sites are
the same one-line shape. `pytest -q tests/test_event_sourced_state_store.py
tests/test_chat_store_input_validation.py` -> 23 passed, 1 failed, where that
failure is `test_failure_before_replace_leaves_old_stream_intact` injecting
`OSError("injected pre-publication failure")` inside the file lock; it fails
identically with these edits reverted, so it is pre-existing on this host.
`ruff check` on the changed files reports `All checks passed!`.

Signed-off-by: kokokoXUY <13682395396@163.com>

Keep the test imports above the module constant (E402).

Author: kokokoXUY

loopx/capabilities/explore/result_log.py

@@ -506,7 +506,7 @@ def append_explore_result_events(
     with exclusive_file_lock(log_path):
         existing_by_id: dict[str, dict[str, Any]] = {}
         if log_path.exists():
-            for line in log_path.read_text(encoding="utf-8").splitlines():
+            for line in log_path.read_text(encoding="utf-8").split("\n"):
                 try:
                     current = json.loads(line)
                 except json.JSONDecodeError:
@@ -546,7 +546,7 @@ def load_explore_result_events(
     if not log_path.exists():
         return []
     events: list[dict[str, Any]] = []
-    for line in log_path.read_text(encoding="utf-8").splitlines():
+    for line in log_path.read_text(encoding="utf-8").split("\n"):
         stripped = line.strip()
         if not stripped:
             continue
@@ -579,7 +579,7 @@ def load_explore_result_events_strict(
     if not log_path.exists():
         return []
     events: list[dict[str, Any]] = []
-    for line_number, line in enumerate(log_path.read_text(encoding="utf-8").splitlines(), start=1):
+    for line_number, line in enumerate(log_path.read_text(encoding="utf-8").split("\n"), start=1):
         stripped = line.strip()
         if not stripped:
             continue

loopx/chat_store.py

@@ -75,7 +75,7 @@ def _read_json(path: Path) -> dict[str, Any]:
 
 def _read_jsonl(path: Path) -> list[dict[str, Any]]:
     try:
-        lines = path.read_text(encoding="utf-8").splitlines()
+        lines = path.read_text(encoding="utf-8").split("\n")
     except OSError:
         return []
     rows: list[dict[str, Any]] = []

loopx/doctor.py

@@ -625,7 +625,7 @@ def latest_promotion_readiness_event(runtime_root: Path, goal_id: str | None = N
         )
     for index_path, current_goal_id, source in indexes:
         try:
-            lines = index_path.read_text(encoding="utf-8").splitlines()
+            lines = index_path.read_text(encoding="utf-8").split("\n")
         except OSError:
             continue
         for line in lines:

loopx/domain_packs/issue_fix.py

@@ -170,7 +170,7 @@ def promote_issue_fix_feasibility_ledger_jsonl(
         canonical_existing: dict[str, Any] | None = None
         if path.exists():
             for index, line in enumerate(
-                path.read_text(encoding="utf-8").splitlines(), start=1
+                path.read_text(encoding="utf-8").split("\n"), start=1
             ):
                 if not line.strip():
                     continue
@@ -530,7 +530,7 @@ def retain_issue_fix_repository_snapshot_jsonl(
     path = Path(ledger_path)
     existing_rows: list[dict[str, Any]] = []
     if path.exists():
-        for line in path.read_text(encoding="utf-8").splitlines():
+        for line in path.read_text(encoding="utf-8").split("\n"):
             try:
                 value = json.loads(line)
             except (TypeError, ValueError):

loopx/domain_state.py

@@ -71,7 +71,7 @@ def upsert_domain_state_jsonl(
         candidate = {**payload, "domain_state_key": key}
         if path.exists():
             for index, line in enumerate(
-                path.read_text(encoding="utf-8").splitlines(), start=1
+                path.read_text(encoding="utf-8").split("\n"), start=1
             ):
                 if not line.strip():
                     continue

loopx/event_sourced_state.py

@@ -578,7 +578,7 @@ class AppendOnlyStateEventStore:
     def load(self) -> list[dict[str, Any]]:
         events: list[dict[str, Any]] = []
         if self.path.exists():
-            for line_number, line in enumerate(self.path.read_text(encoding="utf-8").splitlines(), start=1):
+            for line_number, line in enumerate(self.path.read_text(encoding="utf-8").split("\n"), start=1):
                 if not line.strip():
                     continue
                 try:

tests/test_event_sourced_state_store.py

@@ -12,6 +12,8 @@
     make_state_event,
 )
 
+NEL = "\x85"
+
 
 def test_load_observes_events_appended_by_another_store(tmp_path: Path) -> None:
     event_log = tmp_path / "events.jsonl"
@@ -429,3 +431,30 @@ def test_concurrent_processes_publish_contiguous_batches(tmp_path: Path) -> None
             if row["event_id"].startswith(f"{worker}-")
         ]
         assert positions == list(range(positions[0], positions[0] + 3))
+
+
+def test_load_reads_a_record_whose_value_carries_u0085(tmp_path: Path) -> None:
+    """The event log is one JSON document per LF.
+
+    `json.dumps(..., ensure_ascii=False)` keeps U+0085 inside a value verbatim,
+    and `str.splitlines()` treats it as a line break, so a valid event arrived
+    as two fragments and `load()` raised `StateEventError`.
+    """
+
+    event_log = tmp_path / "events.jsonl"
+    store = AppendOnlyStateEventStore(event_log)
+    event = make_state_event(
+        event_id="evt-raw-separator",
+        goal_id="goal-a",
+        event_type=TODO_ADDED,
+        refs={"todo_id": "todo_raw_separator"},
+        payload={"role": "agent", "title": f"Observe the durable event.{NEL}"},
+        recorded_at="2026-09-06T00:00:00Z",
+    )
+    event_log.write_text(
+        json.dumps(event, ensure_ascii=False) + "\n", encoding="utf-8"
+    )
+
+    loaded = store.load()
+
+    assert [item["event_id"] for item in loaded] == ["evt-raw-separator"]