chore: import upstream snapshot with attribution

docs/en/integrations/postgres/tools/postgres-list-locks.md

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+---
+title: "postgres-list-locks"
+type: docs
+weight: 1
+description: >
+  The "postgres-list-locks" tool lists active locks in the database, including the associated process, lock type, relation, mode, and the query holding or waiting on the lock.
+---
+
+## About
+
+The `postgres-list-locks` tool displays information about active locks by joining pg_stat_activity with pg_locks. This is useful to find transactions holding or waiting for locks and to troubleshoot contention.
+
+This tool identifies all locks held by active processes showing the process ID, user, query text, and an aggregated list of all transactions and specific locks (relation, mode, grant status) associated with each process.
+
+## Compatible Sources
+
+{{< compatible-sources others="integrations/alloydb, integrations/cloud-sql-pg">}}
+
+## Example
+
+```yaml
+kind: tool
+name: list_locks
+type: postgres-list-locks
+source: postgres-source
+description: "Lists active locks with associated process and query information."
+```
+
+### Query
+
+The tool aggregates locks per backend (process) and returns the concatenated transaction ids and lock entries. The SQL used by the tool looks like:
+
+```sql
+SELECT
+    locked.pid,
+    locked.usename,
+    locked.query,
+    string_agg(locked.transactionid::text,':') as trxid,
+    string_agg(locked.lockinfo,'||') as locks
+FROM
+    (SELECT
+      a.pid,
+      a.usename,
+      a.query,
+      l.transactionid,
+      (l.granted::text||','||coalesce(l.relation::regclass,0)::text||','||l.mode::text)::text as lockinfo
+    FROM
+      pg_stat_activity a
+      JOIN pg_locks l ON l.pid = a.pid  AND a.pid != pg_backend_pid()) as locked
+GROUP BY 
+    locked.pid, locked.usename, locked.query;
+```
+
+## Output Format
+
+Example response element (aggregated per process):
+
+```json
+{
+  "pid": 23456,
+  "usename": "dbuser",
+  "query": "INSERT INTO orders (...) VALUES (...);",
+  "trxid": "12345:0",
+  "locks": "true,public.orders,RowExclusiveLock||false,0,ShareUpdateExclusiveLock"
+}
+```
+
+## Reference
+
+| field   | type    | required | description |
+|:--------|:--------|:--------:|:------------|
+| pid     | integer | true     | Process id (backend pid). |
+| usename | string  | true     | Database user. |
+| query   | string  | true     | SQL text associated with the session. |
+| trxid   | string  | true     | Aggregated transaction ids for the process, joined by ':' (string). Each element is the transactionid as text. |
+| locks   | string  | true     | Aggregated lock info entries for the process, joined by '||'. Each entry is a comma-separated triple: `granted,relation,mode` where `relation` may be `0` when not resolvable via regclass. |