feat: cross-chat search FTS snippet highlighting (T111.1)

Replace the ``pov_summary`` column in ``search_all_memories``'s SELECT
with ``snippet(memories_fts, 0, '<mark>', '</mark>', '…', 32)`` so each
match in a result row is wrapped in ``<mark>`` for the search-results
UI. The original ``pov_summary`` is still returned alongside as a
non-highlighted fallback. Template renders ``r.snippet|safe`` — the only
HTML in the snippet output is the configured ``<mark>`` markers, so it
is safe to bypass Jinja's auto-escape.

chat/services/cross_chat_search.py

@@ -26,13 +26,19 @@ def search_all_memories(
     """Search FTS5 across all owners and chats.
 
     Returns rows with ``{memory_id, owner_id, chat_id, scene_id,
-    pov_summary, significance, ts, fts_rank}``, sorted by FTS5 BM25
-    rank ascending (lower rank = stronger match, surfaced first).
+    pov_summary, snippet, significance, ts, fts_rank}``, sorted by FTS5
+    BM25 rank ascending (lower rank = stronger match, surfaced first).
 
     The ``memories`` table has no ``ts`` column; we expose ``created_at``
     (the projector-side row insertion timestamp) under that key so the
     UI does not have to know the storage name.
 
+    ``snippet`` (T111.1) is the FTS5 ``snippet()`` output for the
+    matched ``pov_summary`` column: a windowed excerpt with each match
+    token wrapped in ``<mark>...</mark>`` for the search-results UI to
+    render verbatim. The full ``pov_summary`` is also returned so
+    non-highlighted callers (or fallbacks) keep the original string.
+
     An empty / whitespace-only ``query`` short-circuits to ``[]`` to
     avoid an FTS5 ``MATCH ''`` syntax error and to keep the top-bar
     "no input yet" state from triggering a full-table scan.
@@ -45,9 +51,20 @@ def search_all_memories(
     # from the content table because the FTS index only stores
     # ``pov_summary``. ORDER BY rank ASC because BM25 in FTS5 returns
     # negative scores where lower is better.
+    #
+    # ``snippet(memories_fts, 0, ...)`` (T111.1) targets column 0 of the
+    # FTS virtual table, which is ``pov_summary`` (the only column
+    # indexed by ``CREATE VIRTUAL TABLE memories_fts USING fts5(
+    # pov_summary, ...)`` in migration 0006). SQLite passes the raw
+    # column text through verbatim aside from inserting the configured
+    # before/after match markers, so the only HTML in the output is the
+    # ``<mark>`` we injected — safe to render with ``|safe`` server-side.
     rows = conn.execute(
         "SELECT m.id, m.owner_id, m.chat_id, m.scene_id, "
-        "       m.pov_summary, m.significance, m.created_at, "
+        "       m.pov_summary, "
+        "       snippet(memories_fts, 0, '<mark>', '</mark>', '…', 32) "
+        "       AS snippet, "
+        "       m.significance, m.created_at, "
         "       memories_fts.rank "
         "FROM memories_fts "
         "JOIN memories m ON m.id = memories_fts.rowid "
@@ -64,9 +81,10 @@ def search_all_memories(
             "chat_id": r[2],
             "scene_id": r[3],
             "pov_summary": r[4],
-            "significance": r[5],
-            "ts": r[6],
-            "fts_rank": r[7],
+            "snippet": r[5],
+            "significance": r[6],
+            "ts": r[7],
+            "fts_rank": r[8],
         }
         for r in rows
     ]

chat/templates/search.html

@@ -28,7 +28,15 @@
           {% if r.chat_name %}<span>&middot; {{ r.chat_name }}</span>{% endif %}
           {% if r.scene_label %}<span>&middot; scene {{ r.scene_label }}</span>{% endif %}
         </div>
-        <div class="search-result-summary">{{ r.pov_summary }}</div>
+        {# T111.1: ``r.snippet`` is the FTS5 ``snippet()`` excerpt with
+           each match wrapped in ``<mark>...</mark>``. ``|safe`` is
+           required so the marker tags survive Jinja's auto-escape; the
+           snippet is built by SQLite from indexed text, so the only
+           HTML in the string is the ``<mark>`` we configured (any
+           special chars from the source content are passed through as
+           literal text, NOT as HTML). This is the only ``|safe`` filter
+           on the page — chat_id, owner_name, etc. remain auto-escaped. #}
+        <div class="search-result-summary">{{ r.snippet|safe }}</div>
       </a>
     </li>
     {% endfor %}

chat/web/search.py

@@ -200,6 +200,14 @@ async def search(request: Request, q: str = "", conn=Depends(get_conn)):
                     scene.get("started_at") if scene else None
                 ),
                 "pov_summary": row["pov_summary"],
+                # T111.1: ``snippet`` is the FTS5 windowed excerpt with
+                # ``<mark>`` tags around each match. Falls back to the
+                # full ``pov_summary`` if the row lacks a snippet (which
+                # shouldn't happen on this code path because every
+                # ``raw_results`` row came from a MATCH query, but we
+                # guard defensively so the template never renders
+                # ``None``).
+                "snippet": row.get("snippet") or row["pov_summary"],
                 "significance": row["significance"],
                 "ts": row["ts"],
             }

tests/test_search_ux.py

@@ -136,6 +136,22 @@ def test_result_links_navigate_to_chat(client, tmp_path):
     assert 'href="/chats/chat_a"' in resp.text
 
 
+def test_search_results_include_fts_snippet_with_highlight(client, tmp_path):
+    """T111.1: FTS snippet() wraps each match in ``<mark>...</mark>`` so
+    the result row visually highlights the term that matched.
+
+    The seeded ``pov_summary`` is ``the rabbit darted across chat_a``;
+    SQLite's ``snippet()`` returns the column text with each match token
+    wrapped — searching for ``rabbit`` yields a snippet containing
+    ``<mark>rabbit</mark>``. Assertion is just that the marker appears
+    (the snippet may be truncated with an ellipsis when the indexed text
+    runs longer than the configured token window)."""
+    _seed_two_chats_with_memories(tmp_path / "test.db")
+    resp = client.get("/search?q=rabbit")
+    assert resp.status_code == 200
+    assert "<mark>rabbit</mark>" in resp.text
+
+
 def test_search_results_use_batched_lookups(client, tmp_path):
     """T106: hydration must not fan out to per-row ``get_bot``/
     ``get_chat``/``get_scene`` calls.