[servicememeai]

Purpose

Deliver the in-progress local-object EXDEV fix into the current dev without selecting an archived fork or changing any running storage path.

Scope

• Base: current Server dev@6fc5493, plus the previously reviewed same-shard C/Go staging patch e682060.
• Create each local object temporary file in the destination object's hash-shard directory; atomically rename only after a complete write; preserve existing object identifiers and Seafile repository bindings.
• C/Go failure cleanup and strict published-ID enumeration stay enabled.
• Additional safety correction: whole-store removal now unlinks only valid published 40-hex objects in valid shard directories. Current .cf-tmp-*, previous <object>.XXXXXX remnants, and unrecognized directory contents remain untouched; a nonempty store produces a visible removal failure for maintenance.
• Extend the actual C backend tests to assert that old/new staging remnants and unrecognized shard contents survive removal.

Acceptance / boundaries

• Run bash tests/local_storage/run.sh, cd fileserver && go test ./objstore, and native build CI.
• Run the isolated Linux bind-mount regression with CF_TEST_BIND_MOUNTS=1 on a disposable mount-capable runner before promoting a DEV image (ordinary go test intentionally skips it).
• Cross-repo current-dev assembly is tracked by Docker PR fix(build): restore symbols removed with legacy SQL #23. Hub source isolation is tracked by Hub PR #32.
• No DB migrations, no on-disk format changes, no deployment, no production writes. This PR is not evidence of Etech DEV upload acceptance.