feat(desktop): search sessions by id

tests/test_hermes_state.py

@@ -3786,3 +3786,57 @@ class TestSessionArchive:
         both = {s["id"] for s in db.list_sessions_rich(include_archived=True)}
         assert both == {"live", "hidden"}
         assert db.session_count(include_archived=True) == 2
+
+
+
+class TestSessionIdSearch:
+    """Session id search backs Desktop's Search Sessions UX."""
+
+    def _seed(self, db, sid, *, content="ordinary message", archived=False):
+        db.create_session(session_id=sid, source="cli", model="test-model")
+        db.append_message(session_id=sid, role="user", content=content)
+        if archived:
+            db.set_session_archived(sid, True)
+
+    def test_search_sessions_by_id_matches_exact_prefix_and_substring(self, db):
+        self._seed(db, "20260603_090200_abcd12", content="content without id")
+        self._seed(db, "20260602_111111_other99", content="other content")
+
+        assert [s["id"] for s in db.search_sessions_by_id("20260603_090200_abcd12")] == [
+            "20260603_090200_abcd12"
+        ]
+        assert [s["id"] for s in db.search_sessions_by_id("20260603")] == ["20260603_090200_abcd12"]
+        assert [s["id"] for s in db.search_sessions_by_id("ABCD12")] == ["20260603_090200_abcd12"]
+
+    def test_search_sessions_by_id_respects_limit_and_prioritizes_exact_matches(self, db):
+        self._seed(db, "20260603_090200_abcd12")
+        self._seed(db, "20260603_090200_abcd12_child")
+        self._seed(db, "x_20260603_090200_abcd12")
+
+        ids = [s["id"] for s in db.search_sessions_by_id("20260603_090200_abcd12", limit=2)]
+
+        assert ids == ["20260603_090200_abcd12", "20260603_090200_abcd12_child"]
+
+    def test_search_sessions_by_id_can_include_or_exclude_archived(self, db):
+        self._seed(db, "20260603_090200_live")
+        self._seed(db, "20260603_090200_archived", archived=True)
+
+        included = {s["id"] for s in db.search_sessions_by_id("20260603_090200", include_archived=True)}
+        excluded = {s["id"] for s in db.search_sessions_by_id("20260603_090200", include_archived=False)}
+
+        assert included == {"20260603_090200_live", "20260603_090200_archived"}
+        assert excluded == {"20260603_090200_live"}
+
+    def test_search_sessions_by_id_matches_projected_lineage_root_id(self, db):
+        root = "20260602_235959_root99"
+        tip = "20260603_010000_tip01"
+        db.create_session(session_id=root, source="cli")
+        db.append_message(root, role="user", content="root conversation")
+        db.end_session(root, "compression")
+        db.create_session(session_id=tip, source="cli", parent_session_id=root)
+        db.append_message(tip, role="user", content="continued conversation")
+
+        matches = db.search_sessions_by_id("root99")
+
+        assert [s["id"] for s in matches] == [tip]
+        assert matches[0]["_lineage_root_id"] == root