Indexing: Stop micro-scans after cold-start replay

- Call `mark_full_scan_complete()` after successful cold-start replay in `event_loop.rs` — the index is already up-to-date, so destructive `scan_subtree` micro-scans must not fire
- Without this, navigating directories after app restart triggers `DeleteDescendantsById` + full rescan for each visited directory, wiping millions of entries for minutes

Author: vdavid

apps/desktop/src-tauri/src/indexing/CLAUDE.md

@@ -17,7 +17,7 @@ Full design: `docs/specs/drive-indexing/plan.md`
 - **memory_watchdog.rs** -- Background task monitoring resident memory via `mach_task_info` (macOS). Warns at 8 GB, stops indexing at 16 GB, emits `index-memory-warning` event to frontend. No-op stub on non-macOS. Started from `start_indexing()`.
 - **writer.rs** -- Single writer thread, owns the write connection, processes `WriteMessage` channel (bounded `sync_channel`, 20K capacity, backpressure via blocking). Priority: `UpdateDirStats` before `InsertEntries`. `Flush` variant + async `flush()` method let callers wait for all prior writes to commit. Has both integer-keyed variants (`InsertEntriesV2`, `UpsertEntryV2`, `DeleteEntryById`, `DeleteSubtreeById`, `PropagateDeltaById`) and path-keyed backward-compat variants. The integer-keyed delete/subtree-delete handlers auto-propagate negative deltas via the `parent_id` chain (same pattern as the path-keyed variants). `propagate_delta_by_id` walks the parent chain using `get_parent_id` lookups. `UpsertEntryV2` initializes a zero-valued `dir_stats` row when inserting a NEW directory, so enrichment always has a row (subsequent `PropagateDeltaById` calls update it incrementally). Maintains `AccumulatorMaps` during `InsertEntriesV2` processing (two HashMaps: direct children stats and child dir relationships + an `entries_inserted` counter), cleared on `TruncateData`. On `ComputeAllAggregates`, passes accumulated maps to `aggregator::compute_all_aggregates_with_maps()` to skip expensive full-table-scan SQL queries. Accepts an optional `AppHandle` at spawn time to emit `index-aggregation-progress` events during aggregation (phase, current, total). Also emits `saving_entries` phase progress during `InsertEntriesV2` processing when the expected total is set via `set_expected_total_entries()` (an `Arc<AtomicU64>` shared between the writer thread and the `IndexWriter` handle).
 - **scanner.rs** -- jwalk-based parallel directory walker. `scan_volume()` for full scan, `scan_subtree()` for micro-scans. Uses `ScanContext` (from store.rs) to assign integer IDs and parent IDs during the walk: maintains a `HashMap<PathBuf, i64>` mapping directory paths to assigned IDs. The scan root is mapped to `ROOT_ID` (1). Sends `InsertEntriesV2(Vec<EntryRow>)` batches to the writer. Platform-specific exclusion filters (macOS system paths, Linux virtual filesystems). Physical sizes (`st_blocks * 512`).
-- **micro_scan.rs** -- `MicroScanManager`: bounded task pool (default 3 concurrent), priority queue (`UserSelected` > `CurrentDir`), deduplication, cancellation. Skips after full scan completes.
+- **micro_scan.rs** -- `MicroScanManager`: bounded task pool (default 3 concurrent), priority queue (`UserSelected` > `CurrentDir`), deduplication, cancellation. Skips after full scan completes. Also marked complete after successful cold-start replay (the index is already up-to-date, so destructive micro-scans must not fire).
 - **aggregator.rs** -- Dir stats computation. Bottom-up after full scan (O(N) single pass), per-subtree after micro-scan, incremental delta propagation up ancestor chain for watcher events. Two entry points for full aggregation: `compute_all_aggregates_reported` (loads maps from SQL) and `compute_all_aggregates_with_maps` (accepts pre-built maps from the writer). Both accept an `on_progress: &mut dyn FnMut(AggregationProgress)` callback and delegate to `compute_and_write()` for the shared topological sort + bottom-up computation + batch write. Progress is reported at phase transitions and every ~1% during compute/write loops. `AggregationPhase` enum: `SavingEntries` (flushing writer channel), `LoadingDirectories`, `Sorting`, `Computing`, `Writing`. `backfill_missing_dir_stats` is a catch-up pass that finds directories without `dir_stats` rows and computes their stats bottom-up; triggered after reconciler replay and cold-start replay via `BackfillMissingDirStats` writer message.
 - **watcher.rs** -- Drive-level filesystem watcher. macOS: FSEvents via `cmdr-fsevent-stream` with event IDs and `sinceWhen` replay. Linux: `notify` crate (inotify backend) with recursive watching and synthetic event counter. Other platforms: stub. `supports_event_replay()` lets callers branch on whether journal replay is available.
 - **reconciler.rs** -- Buffers FSEvents during scan (capped at 500K events; overflow sets `buffer_overflow` flag forcing full rescan), replays after scan completes using event IDs to skip stale events. Processes live events for file creates/removes/modifies using integer-keyed write messages (`UpsertEntryV2`, `DeleteEntryById`, `DeleteSubtreeById`, `PropagateDeltaById`). Resolves filesystem paths to entry IDs via `store::resolve_path()` using a read connection passed by callers. Key functions (`process_fs_event`, `emit_dir_updated`) are `pub(super)` so `mod.rs` can call them directly during cold-start replay. `reconcile_subtree()` handles MustScanSubDirs by diffing filesystem vs DB directory-by-directory instead of delete-then-reinsert, making it safe to interrupt at any point.

apps/desktop/src-tauri/src/indexing/event_loop.rs

@@ -509,6 +509,10 @@ pub(super) async fn run_replay_event_loop(
 
     log::info!("Replay: switching to live mode");
     micro_scans.set_replay_active(false);
+    // The index is already complete after a successful replay — mark micro-scans
+    // as superseded so they don't fire destructive scan_subtree calls when the
+    // user navigates directories.
+    micro_scans.mark_full_scan_complete().await;
     let mut reconciler = EventReconciler::new();
     reconciler.switch_to_live();