feat(dashboard_api): GET /webhook/inc-search route (ticket explorer)

Thin passthrough over reporting.fn_inc_search (fleettickets migration 13):
ad-hoc ticket lookup by ticket_id / owner / cluster / status / state / time for
the FleetOps ticket explorer. Mirrors /webhook/inc-dashboard (read-only conn,
jsonb passthrough); validates state in {open,closed,all} and ISO-8601 from/to.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

dashboard_api_rev.py

@@ -368,6 +368,63 @@ def inc_dashboard(
         )
 
 
+# ── INC ticket explorer (search) ──────────────────────────────────────────────
+# Thin passthrough over reporting.fn_inc_search (fleettickets migration 13): ad-hoc
+# ticket lookup by id / engineer / cluster / status / state / time, for historical +
+# current tracking. Returns { count, truncated, limit, state, rows }.
+_INC_STATES = {"open", "closed", "all"}
+
+
+@app.get("/webhook/inc-search")
+def inc_search(
+    ticket_id: str | None = None,   # substring match on ticket_id
+    owner: str | None = None,       # engineer — case-insensitive substring on owner
+    cluster: str | None = None,     # exact tickets.inc.cluster
+    status: str | None = None,      # exact normalized_status
+    state: str = "closed",          # closed | open | all
+    from_: str | None = Query(None, alias="from"),  # closed-at range start (ISO-8601)
+    to: str | None = None,                          # closed-at range end (exclusive, ISO-8601)
+):
+    state = (state or "closed").lower()
+    if state not in _INC_STATES:
+        return _bad_request("state must be one of open|closed|all")
+    f, t = _clean(from_), _clean(to)
+
+    def _parse(v):
+        if not v:
+            return None
+        try:
+            return datetime.fromisoformat(v)
+        except ValueError:
+            return False
+
+    pf, pt = _parse(f), _parse(t)
+    if pf is False or pt is False:
+        return _bad_request("from/to must be ISO-8601 timestamps with an offset/Z")
+    if pf and pt and pf >= pt:
+        return _bad_request("from must be earlier than to")
+
+    try:
+        with get_conn() as conn:
+            with conn.cursor() as cur:
+                cur.execute(
+                    "SELECT reporting.fn_inc_search(%s, %s, %s, %s, %s, %s, %s)",
+                    (_clean(ticket_id), _clean(owner), _clean(cluster), _clean(status), state, f, t),
+                )
+                payload = cur.fetchone()[0] or {}
+        return JSONResponse(payload)  # jsonb body returned unchanged
+    except Exception:
+        log.exception("inc-search failed")
+        return JSONResponse(
+            {
+                "error": {
+                    "type": "unknown",
+                    "message": "Ticket search is unavailable. Try again in a few seconds.",
+                }
+            }
+        )
+
+
 # ── Fleet trips (#002) ───────────────────────────────────────────────────────
 
 _FILTER_OPTIONS_SQL = """