Detect advisory locks at query_parser = auto on single-primary clusters

[mhenrixon]

Fixes #1407.

Root cause

Debugging #1407 against a local build showed the leaked locks were a detection problem, not a cleanup problem. At query_parser = "auto" (the default), RegexParser::use_parser matches only the base session-control command set — CMD_RE, not CMD_RE_ADVISORY. On a cluster where nothing else engages the query parser (single primary, no sharding, no replicas — router_needed() is false), advisory lock statements therefore bypass the parser entirely:

• the client is never marked locked, so it isn't pinned to its backend;
• pg_advisory_unlock can route to a different server connection (Postgres emits a WARNING the app never sees) and the session lock strands on the pooled backend;
• on abrupt client disconnect mid-hold, the server isn't flagged dirty, so the existing pg_advisory_unlock_all() cleanup never runs — [cleanup] no cleanup needed with AdvisoryLocks { locks: {} } in the debug log.

Sharded and read/write-split clusters are unaffected because the parser is already fully engaged for routing.

Fix

Match the advisory regex set (base + advisory patterns) at auto as well, so session advisory locks pin, unlock on the right backend, and get cleaned up on disconnect. The regex gate still only enables the per-request parse for matching statements, so plain traffic is untouched.

Verification

• New unit test test_advisory_lock_auto_level (plus the existing advisory tests all pass).
• End-to-end: local pgdog (transaction mode, single primary, default auto), client runs SELECT pg_try_advisory_lock(424242, 0) and is SIGKILLed while holding the lock.
  • Before: lock remains granted to the pooled backend indefinitely (pg_locks on the server).
  • After: pgdog logs [cleanup] running 3 cleanup queries → SELECT pg_advisory_unlock_all() and the lock is released.
  • Same repro with the client killed mid-query: the backend drains the running statement, then cleanup releases the lock.

[CLAassistant]

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