fix(kanban): heal every nullable v1 tasks column and index assignee after the ALTER pass

Review of the foreign-schema heal found two gaps in what it claimed to cover:

- `_BASE_TASK_COLUMNS` said it listed the nullable/defaulted v1 columns but
  omitted `priority`, `created_by` and `completed_at`. A harness that seeded
  `tasks(id,title,assignee,status,created_at,started_at)` connected fine and
  then failed `list_tasks` with "no such column: priority" (`SELECT *` feeds
  the Task row shape). Add the three entries with DDL copied from SCHEMA_SQL.
- The `assignee` heal was unreachable: `connect()` runs `executescript(SCHEMA_SQL)`
  before `_migrate_add_optional_columns`, and SCHEMA_SQL's
  `CREATE INDEX idx_tasks_assignee_status ON tasks(assignee, status)` aborts
  init on a board without `assignee` before any ALTER runs. Move that index
  into the post-ALTER `CREATE INDEX IF NOT EXISTS` block next to the other
  additive-column indexes; fresh DBs end up with the identical index.

The existing foreign-schema test now seeds the narrowest schema
(`tasks(id,title,status,created_at)`), asserts all ten healed columns match
the fresh DDL, and reads the board back through `list_tasks`.

The "already fully migrated" fixture in
`test_migrate_add_optional_columns_tolerates_concurrent_migration` gains the
v1 `status` column the assignee/status index now needs (a real migrated board
always has it).

hermes_cli/kanban_db.py

@@ -1057,7 +1057,6 @@ CREATE TABLE IF NOT EXISTS kanban_notify_subs (
     PRIMARY KEY (task_id, platform, chat_id, thread_id)
 );
 
-CREATE INDEX IF NOT EXISTS idx_tasks_assignee_status ON tasks(assignee, status);
 CREATE INDEX IF NOT EXISTS idx_tasks_status          ON tasks(status);
 CREATE INDEX IF NOT EXISTS idx_links_child           ON task_links(child_id);
 CREATE INDEX IF NOT EXISTS idx_links_parent          ON task_links(parent_id);

hermes_cli/kanban_db_connect.py

@@ -777,7 +777,10 @@ def init_db(db_path: Optional[Path] = None, *, board: Optional[str] = None) -> P
 _BASE_TASK_COLUMNS = (
     ("body", "body TEXT"),
     ("assignee", "assignee TEXT"),
+    ("priority", "priority INTEGER DEFAULT 0"),
+    ("created_by", "created_by TEXT"),
     ("started_at", "started_at INTEGER"),
+    ("completed_at", "completed_at INTEGER"),
     ("workspace_kind", "workspace_kind TEXT NOT NULL DEFAULT 'scratch'"),
     ("workspace_path", "workspace_path TEXT"),
     ("claim_lock", "claim_lock TEXT"),
@@ -895,6 +898,7 @@ def _migrate_add_optional_columns(conn: sqlite3.Connection) -> None:
     # so a ``CREATE INDEX`` over a missing column in SCHEMA_SQL would abort
     # init on legacy boards before the ALTER TABLE pass runs. ``IF NOT EXISTS``
     # keeps re-running here cheap and correct on fresh DBs.
+    conn.execute("CREATE INDEX IF NOT EXISTS idx_tasks_assignee_status ON tasks(assignee, status)")
     conn.execute("CREATE INDEX IF NOT EXISTS idx_tasks_tenant ON tasks(tenant)")
     conn.execute("CREATE INDEX IF NOT EXISTS idx_tasks_idempotency ON tasks(idempotency_key)")
     conn.execute("CREATE INDEX IF NOT EXISTS idx_tasks_session_id ON tasks(session_id)")

tests/hermes_cli/test_kanban_db.py

@@ -1316,6 +1316,7 @@ def test_migrate_add_optional_columns_tolerates_concurrent_migration(kanban_home
         CREATE TABLE tasks (
             id INTEGER PRIMARY KEY,
             title TEXT NOT NULL,
+            status TEXT NOT NULL DEFAULT '',
             tenant TEXT,
             result TEXT,
             idempotency_key TEXT,
@@ -1354,7 +1355,7 @@ def test_migrate_add_optional_columns_tolerates_concurrent_migration(kanban_home
 
 def test_connect_heals_reduced_tasks_schema_seeded_by_external_harness(kanban_home):
     """A board whose ``tasks`` table was created by an external harness without
-    the base v1 columns (body, workspace_kind, workspace_path, claim_lock,
+    the nullable/defaulted v1 columns (body, assignee, priority, ..., claim_lock,
     claim_expires) but which already has ``task_runs`` must connect: the
     connect-time in-flight backfill SELECTs ``claim_lock`` from ``tasks`` and
     used to raise ``no such column`` on every call (#112953), before
@@ -1363,15 +1364,17 @@ def test_connect_heals_reduced_tasks_schema_seeded_by_external_harness(kanban_ho
     db_path = kanban_home / "foreign.db"
     seed = sqlite3.connect(db_path)
     seed.execute(
-        "CREATE TABLE tasks (id TEXT PRIMARY KEY, title TEXT NOT NULL, assignee TEXT,"
-        " status TEXT NOT NULL, priority INTEGER DEFAULT 0, created_by TEXT,"
-        " created_at INTEGER NOT NULL, started_at INTEGER, completed_at INTEGER)"
+        "CREATE TABLE tasks (id TEXT PRIMARY KEY, title TEXT NOT NULL,"
+        " status TEXT NOT NULL, created_at INTEGER NOT NULL)"
     )
     seed.execute(kbc._REBUILD_SPECS["task_runs"][0])
     seed.commit()
     seed.close()
 
-    healed = {"body", "workspace_kind", "workspace_path", "claim_lock", "claim_expires"}
+    healed = {
+        "body", "assignee", "priority", "created_by", "started_at", "completed_at",
+        "workspace_kind", "workspace_path", "claim_lock", "claim_expires",
+    }
     conn = kbc.connect(db_path)
     try:
         cols = {r["name"] for r in conn.execute("PRAGMA table_info(tasks)")}
@@ -1384,8 +1387,13 @@ def test_connect_heals_reduced_tasks_schema_seeded_by_external_harness(kanban_ho
         assert {c: healed_info[c] for c in healed} == {c: fresh_info[c] for c in healed}
     finally:
         conn.close()
-    # Second connect (the next dispatcher tick) is a no-op, not a re-raise.
-    kbc.connect(db_path).close()
+    # Second connect (the next dispatcher tick) is a no-op, not a re-raise, and
+    # the healed board is queryable (SELECT * reads every v1 column).
+    conn = kbc.connect(db_path)
+    try:
+        assert kb.list_tasks(conn) == []
+    finally:
+        conn.close()
 
 
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