修复自动备份真实挂载解析（07-27-automatic-offhost-backup）

.trellis/spec/hyb-oa/deployment-trialrun.md

@@ -943,6 +943,10 @@ test "$(printf '%s\n' "$actual" | LC_ALL=C sort)" = \
 - Resolve one active Compose server/database pair and verify its build, PGDATA,
   storage mount and database identity before backup. Do not use fixed container
   names or repository-relative runtime data.
+- Parse Docker mount identity from `docker inspect` JSON and require exactly one
+  destination match. Do not split human-formatted Go-template output on tabs or
+  spaces: `println` inserts argument spacing that can make a visually correct
+  line fail exact path comparison on a real daemon.
 - Transfer only a complete `auto-<UTC timestamp>` three-file batch to ARM
   inbox. The forced key allows write-only `rrsync` or an exact finalize command;
   it rejects shell, sender/read and destructive rsync options.
@@ -986,6 +990,9 @@ test "$(printf '%s\n' "$actual" | LC_ALL=C sort)" = \
 
 - Shell syntax plus `run-automatic-backup-contract.sh` using temporary files and
   mocked Docker/SSH boundaries; it must never contact real hosts.
+- Docker mocks must return the real `{{json .Mounts}}` shape consumed by the
+  runner. A simplified tab-delimited mock is not valid evidence for real mount
+  parsing.
 - Focused WeCom alert tests for stdin path redaction, preserved AUTO_BACKUP
   issue identity, first/repeated failure and quarterly reminder behavior.
 - Environment contract assertions for all four scripts, three timers, explicit