perf: round 13 — grouped-view virtualization, notification/login query narrowing, HTTP dedup, locale precompute

Benchmark-gated (BEFORE/AFTER + equivalence/safety gate per change), same
discipline as rounds 2-12. Full write-up in benches/ROUND13.md.

Shipped:
- V1 Grouped views windowed (files route + ResourceList). The grid arm was
  the last unwindowed path (trash is grouped-by-default in grid): each
  swimlane now feeds its own VirtualList, outer container a flex stack.
  vitest gate: 800-item grouped grid mounts <120 .file-item (was 800).
- Q1 get_users_by_ids drops the <=512 KiB avatar image + ui_preferences
  JSONB (notification path never reads them). 30-member fan-out 8.60 ->
  0.25 ms (34.3x), ~7.7 MB off the wire.
- Q2 Login provisioning is_empty() -> SELECT EXISTS for calendar + address
  book (every login). 0.193 -> 0.170 ms, widens with owned-row count.
- Q3 Recent-access prunes only when the upsert inserted (RETURNING xmax=0)
  — a re-access can't grow the set. 0.567 -> 0.324 ms (1.75x).
- L1 Locale supported-codes precomputed once vs rebuilt per anonymous
  request. 616 -> 17.3 ns (35.7x), 18 -> 1 allocs.
- H1 Duplicate /api TraceLayer removed (global stack already wraps it).
  1.86 -> 1.42 us/request, -6 allocs.
- H2 client_ip span field: borrow-only ClientIpDisplay vs owned String.
  187 -> 173 ns, -1 alloc.

Not shipped (discipline): the "media hooks read the blob 3x" lead was a
correctness bug, not a perf dup — the raw-path metadata/faces readers
resolve only for local+unencrypted+single-chunk blobs and silently produce
nothing otherwise. Flagged for maintainers; routing through read_blob_bytes
is a correctness fix (perf-neutral-to-negative), not a benchmark-gated
perf change.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BfidAJD5AHw23jtvBUNamB

src/infrastructure/adapters/calendar_storage_adapter.rs

@@ -39,6 +39,14 @@ impl CalendarStorageAdapter {
             event_repository,
         }
     }
+
+    /// Delegates to [`CalendarPgRepository::has_owned_calendar`] — the
+    /// `EXISTS` short-circuit used by the login provisioning hook instead
+    /// of hydrating every owned calendar to test emptiness
+    /// (benches/ROUND13.md §Q2).
+    pub async fn has_owned_calendar(&self, owner_id: Uuid) -> Result<bool, DomainError> {
+        self.calendar_repository.has_owned_calendar(owner_id).await
+    }
 }
 
 impl CalendarStoragePort for CalendarStorageAdapter {

src/infrastructure/repositories/pg/address_book_pg_repository.rs

@@ -16,6 +16,23 @@ impl AddressBookPgRepository {
     pub fn new(pool: Arc<PgPool>) -> Self {
         Self { pool }
     }
+
+    /// `EXISTS` short-circuit for the login provisioning hook — the old
+    /// `get_address_books_by_owner(..).is_empty()` hydrated every owned
+    /// `AddressBook` row on EVERY login just to test emptiness (the ROUND9
+    /// §7 COUNT→EXISTS pattern; benches/ROUND13.md §Q2).
+    pub async fn has_owned_address_book(&self, owner_id: Uuid) -> Result<bool, DomainError> {
+        let exists: bool = sqlx::query_scalar(
+            "SELECT EXISTS(SELECT 1 FROM carddav.address_books WHERE owner_id = $1)",
+        )
+        .bind(owner_id)
+        .fetch_one(&*self.pool)
+        .await
+        .map_err(|e| {
+            DomainError::database_error(format!("Failed to probe owned address books: {}", e))
+        })?;
+        Ok(exists)
+    }
 }
 
 impl AddressBookRepository for AddressBookPgRepository {

src/infrastructure/repositories/pg/calendar_pg_repository.rs

@@ -16,6 +16,24 @@ impl CalendarPgRepository {
     pub fn new(pool: Arc<PgPool>) -> Self {
         Self { pool }
     }
+
+    /// `EXISTS` short-circuit for the login provisioning hook, which only
+    /// needs to know whether the user owns ANY calendar. The old
+    /// `list_calendars_by_owner(..).is_empty()` hydrated every owned
+    /// `Calendar` row (8 cols incl. description/color TEXT) on EVERY login
+    /// just to test emptiness — the ROUND9 §7 `Drive::is_empty` COUNT→EXISTS
+    /// pattern (benches/ROUND13.md §Q2).
+    pub async fn has_owned_calendar(&self, owner_id: Uuid) -> CalendarRepositoryResult<bool> {
+        let exists: bool =
+            sqlx::query_scalar("SELECT EXISTS(SELECT 1 FROM caldav.calendars WHERE owner_id = $1)")
+                .bind(owner_id)
+                .fetch_one(&*self.pool)
+                .await
+                .map_err(|e| {
+                    DomainError::database_error(format!("Failed to probe owned calendars: {}", e))
+                })?;
+        Ok(exists)
+    }
 }
 
 impl CalendarRepository for CalendarPgRepository {

src/infrastructure/repositories/pg/recent_items_pg_repository.rs

@@ -96,19 +96,24 @@ impl RecentItemsRepositoryPort for RecentItemsPgRepository {
         Ok(items)
     }
 
-    async fn upsert_access(&self, user_id: Uuid, item_id: &str, item_type: &str) -> Result<()> {
-        sqlx::query(
+    async fn upsert_access(&self, user_id: Uuid, item_id: &str, item_type: &str) -> Result<bool> {
+        // `xmax = 0` on the affected row is the canonical upsert idiom for
+        // "this was an INSERT, not a DO UPDATE" — lets the caller skip the
+        // prune round-trip on the common re-access (UPDATE) path
+        // (benches/ROUND13.md §Q3).
+        let inserted: bool = sqlx::query_scalar(
             r#"
             INSERT INTO auth.user_recent_files (user_id, item_id, item_type, accessed_at)
             VALUES ($1, $2, $3, CURRENT_TIMESTAMP)
             ON CONFLICT (user_id, item_id, item_type)
             DO UPDATE SET accessed_at = CURRENT_TIMESTAMP
+            RETURNING (xmax = 0)
             "#,
         )
         .bind(user_id)
         .bind(item_id)
         .bind(item_type)
-        .execute(&*self.db_pool)
+        .fetch_one(&*self.db_pool)
         .await
         .map_err(|e| {
             error!("Database error upserting recent item access: {}", e);
@@ -119,7 +124,7 @@ impl RecentItemsRepositoryPort for RecentItemsPgRepository {
             )
         })?;
 
-        Ok(())
+        Ok(inserted)
     }
 
     async fn remove_item(&self, user_id: Uuid, item_id: &str, item_type: &str) -> Result<bool> {

src/infrastructure/repositories/pg/user_pg_repository.rs

@@ -414,6 +414,16 @@ impl UserRepository for UserPgRepository {
     /// recipient expansion). Missing ids are silently skipped — the
     /// caller treats absent rows as "no such recipient", same as
     /// `get_user_by_id` returning `NotFound` for a single lookup.
+    ///
+    /// Notification-recipient projection: the up-to-512 KiB avatar `image`
+    /// and the `ui_preferences` JSONB are NOT hydrated (both come back as
+    /// `None`/`Null`) — the sole caller
+    /// (`RecipientNotificationService`) reads only the email/eligibility
+    /// fields, and a group fan-out of M members otherwise detoasted +
+    /// shipped + parsed M avatars purely to discard them (the ROUND12 §Q1
+    /// avatar-narrowing pattern; benches/ROUND13.md §Q1). If a future
+    /// caller needs the avatar, add a wide sibling rather than widening
+    /// this one back.
     async fn get_users_by_ids(&self, ids: Vec<Uuid>) -> UserRepositoryResult<Vec<User>> {
         if ids.is_empty() {
             return Ok(Vec::new());
@@ -425,9 +435,8 @@ impl UserRepository for UserPgRepository {
                 id, username, email, password_hash, role::text as role_text,
                 storage_quota_bytes, storage_used_bytes,
                 created_at, updated_at, last_login_at, active,
-                oidc_provider, oidc_subject, image, is_external,
-                given_name, family_name, email_verified_at, preferred_locale, notify_on_share,
-                ui_preferences
+                oidc_provider, oidc_subject, is_external,
+                given_name, family_name, email_verified_at, preferred_locale, notify_on_share
             FROM auth.users
             WHERE id = ANY($1)
             "#,
@@ -460,14 +469,14 @@ impl UserRepository for UserPgRepository {
                     row.get("active"),
                     row.get("oidc_provider"),
                     row.get("oidc_subject"),
-                    row.get("image"),
+                    None, // image — not projected (notification-recipient path)
                     row.get("is_external"),
                     row.get("given_name"),
                     row.get("family_name"),
                     row.get("email_verified_at"),
                     row.get("preferred_locale"),
                     row.get("notify_on_share"),
-                    row.get::<serde_json::Value, _>("ui_preferences"),
+                    serde_json::Value::Null, // ui_preferences — not projected
                 )
             })
             .collect())