Bug: `lore stage --dry-run` persists the staged state (dry run is not dry)

[Segurad27]

Environment

• Lore v0.8.4 (CLI + loreserver), Windows 11
• Local server over lore://127.0.0.1, single user, single branch

Summary

lore stage . --dry-run is documented as "only report what would have been
changed and perform no changes", but it persists the computed staged state.
A subsequent real lore stage . reports "No changes staged" because the
work is already done, and lore status shows the full staged file list —
which a following lore commit happily uses.

Repro

# with any uncommitted changes present (marked dirty)
lore stage . --dry-run     # prints "Staged repository state <signature>"
lore stage .               # prints "No changes staged"
lore status                # "Changes staged for commit:" lists every file
lore commit "msg"          # commits the dry-run's staged state

Expected

After --dry-run, no staged state exists; the follow-up real lore stage .
stages the changes fresh.

Actual

The dry-run's staged state is persisted and consumed by later commands.

Impact

Low when the preview matched intent, but "preview" operations that mutate
state are an automation hazard: a dry-run followed by an abort still leaves
a staged state, and a staged state blocks synchronization
("Unable to sync when there is a staged state") — so an abandoned preview
can break the next unrelated lore sync until the user discovers
lore unstage.

Workaround

Treat stage --dry-run as a real stage; run lore unstage <path> to clean
up after an abandoned preview.

[piyushbag]

Confirmed the report: stage --dry-run still called store_staged_anchor, so preview runs left a persisted staged state behind.

I opened a PR that guards staged-anchor persistence with dry_run() in the stage paths (matching commit/revert), while keeping stage events/counts for preview output. Added stage_dry_run_no_persist in lore-revision/tests/stage.rs.