cleanup(tcfs-sync): dead-code + DRY in the conflict/reconcile chokepoints (pre .git-aware-resolution)

[Jesssullivan]

What

A small, behavior-preserving dead-code + DRY cleanup of the conflict-resolution / reconcile chokepoints in crates/tcfs-sync, prepping them for the (separate, later) .git-aware conflict-resolution feature. No sync/conflict behavior changes.

Items (each behavior-preserving)

1. reconcile.rs classify_path — delete stale dead comment block. Removed the trailing comment after the (None, None, None) match arm describing a "Local exists, not remote, but was tracked" case that is already handled by the (Some, None, Some) arm above. Comment-only; no logic change.

2. reconcile.rs list_remote_index — use DIR_MARKER_SUFFIX const. Replaced the literal "/.tcfs_dir" with the existing const DIR_MARKER_SUFFIX: &str = "/.tcfs_dir" (byte-identical value, already used in list_remote_empty_dirs). Value-identical.

3. conflict.rs compare_clocks — collapse two identical Conflict arms. The Some(Ordering::Equal) and None arms built byte-identical ConflictInfo; merged into one Some(Ordering::Equal) | None => arm with a single now / unwrap_or_default(). Both inputs still produce the same SyncOutcome::Conflict with the same ConflictInfo. Logically identical.

4. reconcile.rs — extract the shared outcome -> ReconcileAction tail. The four-arm match mapping SyncOutcome to ReconcileAction was byte-identical in compare_both_exist and compare_both_exist_symlink. Extracted into one private helper and called from both sites. Pure code motion, zero behavior change.

   Helper signature:

   fn outcome_to_action(
       outcome: crate::conflict::SyncOutcome,
       rel_path: &str,
       local_path: &Path,
       remote_entry: &RemoteIndexEntry,
   ) -> ReconcileAction

5. git_safety.rs — delete dead pub fn restore_git_from_bundle. grep -rn restore_git_from_bundle crates/ tests/ showed zero callers; it is superseded by restore_git_bundle_into (the fn actually used by tcfs-cli and engine.rs). Removed.

Deliberately excluded (rejected as unsafe — left exactly as-is)

These are behavior-changing / feature-PR territory and were intentionally not touched:

• reconcile.rs Conflict arm / mark_conflict swap (behavior-changing).
• conflict.rs (true, true) => None (needed for match exhaustiveness).
• AutoResolver / ConflictResolver / Resolution variants / compare_clocks signature / partial_cmp_vc / is_concurrent / chunk_hashes / is_legacy (all live, incl. integration tests).
• reconcile.rs UpToDate-on-hash-failure policy + the SystemTime double-compute.
• The refs/heads/*.lock literal-not-glob in git_safety.rs (left for the feature PR).

Why now

These are the chokepoints the upcoming .git-aware conflict-resolution feature will modify. Clearing dead code and the duplicated outcome -> action mapping first keeps the two reconcile paths (regular file + symlink) in lockstep and shrinks the feature PR's blast radius. See the G5-git-5 CONCURRENT-WRITE CORRUPTION gap in docs/ops/repo-roam-test-plan-2026-06-08.md, which is expected to fail until conflict resolution is made .git-aware.

Validation (full local CI gate)

• cargo fmt --all -- --check — clean (exit 0).
• cargo clippy --workspace --all-targets — zero warnings in tcfs-sync; the only workspace warnings are 2 pre-existing needless_borrow in crates/tcfsd/src/grpc.rs (lines 1442, 1876), confirmed identical on origin/main and unrelated to this diff.
• cargo test -p tcfs-sync — 324 passed, 0 failed.
• cargo test -p tcfsd — 58 passed, 0 failed (run because conflict.rs is consumed by tcfsd).