Catch the runbooks up with the query API they describe

Phase 2 unified the two query languages behind one endpoint and renamed
the request field, and the runbooks were never updated. Following them
today does not work:

  {"sql": ...}                 -> 400 query must not be empty
  POST /api :8080/search       -> 404, the route no longer exists

Both appear in the Phase 0 and Phase 1 runbooks and in the
windows-fixture README. That matters more than a normal doc typo,
because status.md cites the Phase 0 runbook as the record of how Phase
0 was verified -- so the documented verification procedure is one
nobody can re-run as written.

The Phase 1 step is rewritten rather than search-and-replaced: it
checked the SQL and full-text paths against two different endpoints,
and its exit criterion (the same record_id from both) now has to be
expressed against /query twice, once with SQL and once with a bare
word.

Phase 0's expected output for SELECT 1 also gained a warnings field
since it was written.

Every command here was run against a live stack before being written
down, including confirming both paths return the same record_id.

Signed-off-by: John Coffey <[email protected]>

docs/phase-0-runbook.md

@@ -75,8 +75,11 @@ curl http://localhost:8080/healthz
 
 curl -X POST http://localhost:8080/query \
   -H 'Content-Type: application/json' \
-  -d '{"sql": "SELECT 1"}'
-# -> {"columns":["1"],"rows":[[1]]} (exact column name may vary by ClickHouse version)
+  -d '{"query": "SELECT 1"}'
+# -> {"columns":["1"],"rows":[[1]],"warnings":[...]}
+#    (exact column name may vary by ClickHouse version; `warnings` carries
+#    costguard's assessment and is present on every response that has
+#    something to say about the query's cost)
 ```
 
 This confirms `api` can reach `clickhouse` before you go looking for bugs
@@ -157,7 +160,7 @@ ORDER BY timestamp DESC LIMIT 100`), and look for a row with
 ```sh
 curl -X POST http://localhost:8080/query \
   -H 'Content-Type: application/json' \
-  -d '{"sql": "SELECT * FROM logs ORDER BY timestamp DESC LIMIT 10"}'
+  -d '{"query": "SELECT * FROM logs ORDER BY timestamp DESC LIMIT 10"}'
 ```
 
 **Or via cairnobsctl, just to confirm api is up (doesn't check the data