perf: round 4 — one-pass row paths, drive-selector cache, CalDAV single-parse, streamed Azure, batched hydration

Nine benchmark-gated changes (benches/ROUND4.md; every one ships with a
BEFORE/AFTER bench + equivalence gate, rollback rule as ROUND2/3):

- Row→entity path build: one-pass StoragePath::from_folder_and_name /
  from_joined + normalize_storage_name_owned + alloc-free Display —
  743→417 ns/file-row (1.78x), −5 allocs/row on every listing surface.
- WebDAV drive-selector: per-user readable_cache (single-flight, 30 s
  TTL, explicit invalidation incl. membership + group changes) replaces
  the grants join per request — 441 µs → 0.8 µs (~550x), 0 queries warm.
- CalDAV from_ical/update_ical_data: 8 full IcalParser runs per VEVENT
  → 1 (7.1x per PUT, 4.4x on 50-event imports); alloc-free split_vevents,
  chunk scan without the whole-body uppercase copy (1.4x), borrowed-key
  UID grouping (1.3x), REPORT props no longer cloned.
- PROPFIND emit: partition Vecs dropped (single-pass 404 list) + stack
  rendered RFC 3339/2822 dates, sizes, quoted etags (common::fmt,
  chrono-byte-identical, sweep-tested) on both DAV surfaces — 1.22x
  per page, 17.9→12.0 allocs/row.
- Grant-listing hydration: calendars/address books/playlists batch
  hydrate via = ANY($1) — 15 serial queries → 1 (~13x per sync poll).
- user-flags cache: get→insert → try_get_with single-flight (32→1
  queries per cold herd).
- Azure downloads: whole-blob Vec buffering → streamed SDK pages —
  TTFB 349→4 ms (87x), peak heap 480→1.9 MiB (254x) on 256 MiB blobs;
  new OXICLOUD_AZURE_ENDPOINT_URL override (Azurite/bench hook).
- Face indexing: unbounded per-image tokio::spawn → core-count
  semaphore, permit before blob read — peak heap 1175→176 MiB (6.7x).

Checks: cargo fmt, clippy --all-features --all-targets -D warnings,
cargo test --workspace (523 passed) + --features test_utils. hurl API
suite and dockerized integration DB not runnable in this environment —
left to CI.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017aJu9ghvuT8WqC31ZEGTBA

src/application/services/subject_group_service.rs

@@ -44,6 +44,11 @@ pub struct SubjectGroupService {
     /// 30 s TTL. Without this, fresh group-mediated drive grants
     /// don't appear in `/api/drives` for up to 30 s after `add_member`.
     engine: Arc<crate::infrastructure::services::pg_acl_engine::PgAclEngine>,
+    /// Same freshness contract for the drive repository's per-user
+    /// readable-drives cache: a membership change on a group that holds
+    /// drive grants changes every affected user's visible drive list,
+    /// so the cached lists drop alongside `user_groups_cache`.
+    drive_repo: Arc<crate::infrastructure::repositories::pg::DrivePgRepository>,
 }
 
 impl SubjectGroupService {
@@ -52,12 +57,14 @@ impl SubjectGroupService {
         pool: Arc<PgPool>,
         user_storage: Arc<UserPgRepository>,
         engine: Arc<crate::infrastructure::services::pg_acl_engine::PgAclEngine>,
+        drive_repo: Arc<crate::infrastructure::repositories::pg::DrivePgRepository>,
     ) -> Self {
         Self {
             repo,
             pool,
             user_storage,
             engine,
+            drive_repo,
         }
     }
 
@@ -426,6 +433,7 @@ impl SubjectGroupService {
         // call for up to 30 s.
         for uid in self.invalidation_targets(member).await? {
             self.engine.invalidate_user_groups_cache(uid).await;
+            self.drive_repo.invalidate_readable_for_user(uid).await;
         }
 
         tracing::info!(
@@ -525,6 +533,7 @@ impl SubjectGroupService {
         // for up to 30 s, surfacing grants they no longer have.
         for uid in self.invalidation_targets(member).await? {
             self.engine.invalidate_user_groups_cache(uid).await;
+            self.drive_repo.invalidate_readable_for_user(uid).await;
         }
 
         tracing::info!(
@@ -634,7 +643,9 @@ mod integration_tests {
         // future test starts exercising real authz lookups.
         let engine =
             Arc::new(crate::infrastructure::services::pg_acl_engine::PgAclEngine::new_stub());
-        SubjectGroupService::new(repo, pool, user_storage, engine)
+        let drive_repo =
+            Arc::new(crate::infrastructure::repositories::pg::DrivePgRepository::new(pool.clone()));
+        SubjectGroupService::new(repo, pool, user_storage, engine, drive_repo)
     }
 
     async fn first_admin(pool: &sqlx::PgPool) -> Uuid {