Without base_commit, export diffs against the current guest HEAD.
If the worker ran git commit inside the VM, HEAD advanced and the
diff came back empty — committed work was silently lost.
With base_commit set to the head_commit from workspace.prepare,
the diff uses that fixed point instead. After git add -A the index
holds the full working state, so git diff --cached <base_commit>
captures everything: committed deltas (HEAD moved past base) and
any uncommitted changes on top, in one patch, applied with the
same git apply flow.
- WorkspaceExportParams gains base_commit
- WorkspaceExportResult echoes back the ref actually used
- CLI gains --base-commit flag
- Tests assert scripts use the caller-supplied ref and that
omitting it falls back to HEAD
guest.session.send — write to a pipe-mode session's stdin without
holding the exclusive attach. The daemon dials a fresh SSH connection,
uploads the payload to a temp file, and cats it into the session's
named FIFO. Linux atomicity for writes ≤ PIPE_BUF covers all pi RPC
JSONL lines. Attach exclusivity is unchanged.
vm.workspace.export — pull changes from guest back to host. Runs
`git add -A && git diff --cached HEAD --binary` inside the guest via a
new RunScriptOutput helper on guest.Client (stdout-only capture,
distinct from RunScript which merges stderr). Returns a binary-safe
patch and a list of changed files. CLI writes the patch to stdout for
`| git apply` or to a file via --output.
RunScriptOutput is implemented as a direct SSH session (same pattern as
runSession) rather than going through StartCommand/StreamSession to
avoid closing the underlying Client, which is required since
ExportVMWorkspace calls it twice on the same connection.
New files: internal/daemon/workspace_test.go
