fix(mft): restore OFFLINE sort + custom format for parity (5/6 drives pass)

Commit 90ee522 removed all sort_directory_children() calls to match C++
LIVE behavior, but this broke OFFLINE mode (0/6 drives passing). OFFLINE
paths need sorting for deterministic output since MFT dump parsing order
differs from live IOCP traversal.

Changes:
- Restore sort_directory_children() before compute_tree_metrics() in all
  3 OFFLINE code paths: builder.rs, persistence.rs, merge.rs
- Add --format custom to verify_parity.rs to match C++ baseline footer

Verified: D, E, G, M, S all SORTED MATCH. F is known deferred (Bug 3).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: githubrobbi

crates/uffs-mft/src/index/builder.rs

@@ -465,7 +465,15 @@ impl MftIndex {
         tracing::debug!("[TRIP] MftIndex::from_parsed_records -> Phase 2: ExtensionIndex::build");
         index.extension_index = Some(ExtensionIndex::build(&index));
 
-        // 2. Compute tree metrics for directory statistics (Phase 5)
+        // 2. Sort directory children for deterministic OFFLINE output (Phase 4)
+        // CRITICAL: OFFLINE path (from_parsed_records) requires sorted children
+        // for deterministic CSV output order. LIVE paths (to_index.rs) do NOT
+        // sort to match C++ behavior (reverse MFT parse order).
+        tracing::debug!("[TRIP] MftIndex::from_parsed_records -> Phase 4: sort_directory_children");
+        index.sort_directory_children();
+
+        // 3. Compute tree metrics for directory statistics (Phase 5)
+        // Must run AFTER sorting in OFFLINE path for deterministic results.
         tracing::debug!("[TRIP] MftIndex::from_parsed_records -> Phase 5: compute_tree_metrics");
         index.compute_tree_metrics();
 

crates/uffs-mft/src/index/merge.rs

@@ -54,6 +54,9 @@ impl MftIndex {
         debug!("🔨 Building extension index...");
         self.extension_index = Some(ExtensionIndex::build(self));
 
+        debug!("🔨 Sorting directory children...");
+        self.sort_directory_children();
+
         debug!("🔨 Computing tree metrics...");
         self.compute_tree_metrics();
 

crates/uffs-mft/src/reader/persistence.rs

@@ -609,6 +609,10 @@ impl MftReader {
             }
         }
 
+        // Sort directory children for deterministic output
+        // CRITICAL for OFFLINE path: ensures consistent ordering across runs
+        index.sort_directory_children();
+
         // Compute tree metrics
         index.compute_tree_metrics();
 

scripts/verify_parity.rs

@@ -994,6 +994,8 @@ fn regenerate_rust_output(
             drive_letter,
             "--tz-offset",
             &tz_str,
+            "--format",
+            "custom",  // Match C++ baseline footer format
             "--out",
             &rust_output.to_string_lossy(),
         ])