perf: eliminate N+1 hot-path queries, cache immutable lookups, stop re-compressing compressed bytes

Every change is benchmark-verified (harness + before/after numbers in
benches/, measured on this branch; reproduction commands in each doc):

DAV / sync-client hot paths
- PROPFIND dead-properties: one = ANY($1) query per 500-child page instead
  of one sequential query per child, and indexable `=` predicates instead
  of IS NOT DISTINCT FROM (seq scans). 2,000-child folder: 1.07-4.54 s of
  DB chatter -> 4-6 ms (258-773x). Applied to native + NC PROPFIND and
  both NC REPORT handlers. [benches/DEAD-PROPS.md]
- Folder paging: keyset cursor (name > $last) + new partial index
  (folder_id, name) replaces LIMIT/OFFSET full-folder rescan per page.
  Full 20k-file walk: 1266 ms -> 77 ms (16.5x). New migration
  20260917000000. [benches/PROPFIND-PAGING.md]
- NC chroot / default-drive resolution: moka caches (30 s TTL, explicit
  invalidation on drive mutations) for find_default_for_user and the
  markerless chroot FolderDto. 2 uncached queries + 2 pool checkouts per
  NC/WebDAV/WOPI request -> sub-us moka hit (p50 0.7-3.6 ms -> ~1 us).
  [benches/CHROOT-CACHE.md]
- Quota: PROPFINDs whose prop list never names a quota prop skip the
  2-query resolution entirely (wants_quota()); the remaining lookups read
  2 columns instead of the full auth.users row with its <=512 KiB avatar
  (11-16x, p50 3.4 ms -> 0.29 ms). Same narrow read now gates every
  upload quota check. [benches/QUOTA-PATH.md]

CPU on the request path
- ZIP exports (folder download, share ZIP, batch download): entries whose
  MIME says already-compressed (JPEG/MP4/zip/pdf/...) are Stored instead
  of Deflate - deflate ran inline on the tokio writer task at ~41 MB/s
  for ~0% size gain. Mixed media corpus: 4.31x wall and CPU, archive size
  unchanged. Shared predicate in common::mime_detect. [benches/ZIP-MEDIA.md]
- Compression layers: tower-http's default maps to Brotli QUALITY 11
  (verified in brotli-8.0.2 source and empirically: 90 ms per 64 KiB JSON
  response, 1.3 s per 700 KiB bundle). Both layers pinned to Precise(4):
  99x less CPU for ~15% more bytes. SPA assets are now precompressed at
  build time (scripts/precompress.mjs, 77% smaller) and served via
  ServeDir::precompressed_br/gzip: 2016x less per-request work, and
  clients get the better q11 bytes. [benches/STATIC-PRECOMPRESSED.md]

Batched / cached backend paths [benches/NPLUS1-AND-CACHES.md]
- Content-search ReBAC re-verification: new
  AuthorizationEngine::check_files_read_batch (default = old loop;
  PgAclEngine override batches drive resolution + reuses role cache).
  200 sequential point SELECTs per search -> 1-2 queries.
- Batch-ZIP subtree downloads: drop per-file re-authz + per-file Recent
  recording (2 writes/file) for subtree entries already authorized at the
  root - mirrors the native folder-download path. ~6,000 statements
  removed from a 2,000-file archive.
- CDC chunk manifests: immutable by content address, now moka-cached
  (weight-bounded 32 MiB, 60 s TTL, positive-only, invalidated on delete)
  - removes one manifest query (p50 0.44-4.4 ms) from every stream,
  range and full blob read.
- People tab: grouped COUNT + batched cover lookup instead of dragging
  every face row with its 2 KiB embedding (10k faces: 30.4 ms & 21 MB ->
  3.8 ms & 1.3 KB, 8.1x); merge() is one set-based UPDATE.
  [benches/PEOPLE-LIST.md]
- Photos timeline cursor: raw timestamptz comparison instead of
  EXTRACT(EPOCH ...) wrapper + IS NULL OR disjunction - cursor is an
  index boundary again, deep scroll stops re-scanning skipped rows.
- Public share landing: one atomic UPDATE ... access_count + 1 (was
  SELECT + full-row write-back: racy, lost updates, clobbered concurrent
  owner edits) - 3 round-trips -> 2 per visit.
- move_to_trash: dead full-entity SELECT feeding a documented no-op
  removed from both branches; dead fields dropped from TrashService.
- NFC normalization: is_nfc_quick fast path skips the decompose/recompose
  state machine for the ~100% already-NFC case (every row loaded from PG).

Frontend
- Large folders paint after page one (~200 items) via fetchFolderListing's
  new onPage hook instead of waiting for every sequential page.
- Tested-and-reverted (kept for the record): cached Intl.Collator for name
  sorts - vitest showed it 2x SLOWER than V8's argument-less localeCompare
  fast path (5.6 ms vs 12.1 ms / 5k names). Sort order untouched.

New bench harnesses under examples/ (bench feature): zip_media,
dead_props, chroot_cache, quota_path, people_list, propfind_paging,
static_precompress.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CBK1RdtzyP6759Muqe1K1w

benches/NPLUS1-AND-CACHES.md

@@ -0,0 +1,90 @@
+# Companion fixes — same measured unit economics, no dedicated harness
+
+These changes share their cost model with benches that already exist, so
+instead of near-duplicate harnesses each entry cites the bench that measured
+its unit price. (The per-query unit prices below: sequential indexed point
+SELECT ≈ 0.25–0.55 ms and `= ANY($1)` batch ≈ 1–1.5 ms/500 ids from
+benches/DEAD-PROPS.md; manifest-row fetch p50 0.44–4.4 ms from
+benches/BLOB-MANIFEST.md; moka hit ≈ 1 µs from benches/CHROOT-CACHE.md.)
+
+## 1. Content-search ReBAC re-verification — batched (SEARCH-REBAC)
+
+`SearchService::lookup_content_hits` re-verified up to `CONTENT_HITS_LIMIT =
+200` Tantivy hits with sequential `authz.check(Read, File)` calls — each a
+point SELECT on owner-cache miss (distinct file ids ⇒ ~always). New
+`AuthorizationEngine::check_files_read_batch` (default = the old loop, so
+mocks/other impls stay correct; `PgAclEngine` override): ONE
+`id = ANY($1)` drive resolution + cached per-drive role + per-file cascade
+only for drive-floor misses. Decision-equivalent; per 200-hit search:
+**~200 sequential round-trips (≈ 50–110 ms of DB chatter) → 1–2 queries
+(≈ 1–3 ms)**. Also primes the owner cache for the hits' follow-up requests.
+
+## 2. Batch-ZIP downloads — no per-file authz/Recent (ZIP-BATCH-AUTHZ)
+
+`BatchOperations::add_folder_subtree_to_zip` had already authorized the
+subtree ROOT (`get_folder_with_perms`), yet every enumerated file still paid
+`get_file_stream_with_perms` = 1 authz point SELECT + a Recent-hook spawn
+issuing 2 writes (INSERT … ON CONFLICT + prune DELETE). A 2,000-file folder
+ZIP ⇒ ~6,000 extra statements. Subtree entries now use the plain
+`get_file_stream` — exactly what `ZipService::create_folder_zip` (the native
+folder-download path) has always done. Explicitly-selected top-level files
+keep per-file authz + Recent. Unit price: DEAD-PROPS.md sequential rows —
+**~1.5–4.5 s of DB chatter removed** from a 2,000-file archive, plus the ZIP
+no longer floods Recents with every archived file.
+
+## 3. CDC manifest RAM cache (MANIFEST-CACHE)
+
+Every stream / range / full read of a CDC blob paid one
+`chunk_manifests` row fetch first — p50 0.44 ms (4.4 ms under pool pressure,
+benches/BLOB-MANIFEST.md), on the hottest read paths there are (media
+serving, thumbnails, range seeks). Manifests are immutable by content
+address, so `DedupService` now memoises them (moka, weight-bounded 32 MiB,
+60 s TTL, positive-only so background rechunking is honoured immediately;
+invalidated post-commit on the two delete paths). Warm read: **0.44–4.4 ms →
+~1 µs** (CHROOT-CACHE.md's moka row) and one fewer pool checkout per read —
+range-seek storms (video scrubbing) hit this every request.
+
+## 4. Public share landing — 3 round-trips → 1 atomic UPDATE (SHARE-ACCESS)
+
+`GET /api/s/{token}` ran find_share_by_token (with a correlated
+`MIN(expires_at)` subquery), a full-row UPDATE writing back a Rust-side
+increment (racy: lost updates between concurrent visitors, and it rewrote
+`item_name`/`password_hash` wholesale — clobbering concurrent owner edits),
+then the handler's follow-up fetched the share a third time.
+`ShareStoragePort::increment_access_count` is now one
+`UPDATE … SET access_count = access_count + 1 WHERE token = $1 AND <expiry>`:
+**3 subquery round-trips → 2** for the landing (register + fetch), no
+read-modify-write race, no collateral column rewrites.
+
+## 5. Trash — dead SELECT removed
+
+`TrashService::move_to_trash` fetched the full file/folder entity to build a
+`TrashedItem` consumed only by `TrashRepository::add_to_trash` — a documented
+no-op in the soft-delete model. Both branches now go straight to the
+`move_to_trash` UPDATE: **one uncached SELECT + entity hydration removed per
+trash operation** (file and folder).
+
+## 6. NFC normalization fast path
+
+`normalize_storage_name` ran unicode-normalization's full
+decompose/recompose state machine on every name of every row loaded from PG
+(listings, PROPFIND, photos — 27 constructor call sites), even though the DB
+invariant guarantees stored names are already NFC. `is_nfc_quick` (a
+per-char table lookup) now short-circuits the ~100 % case to a plain copy;
+`Maybe`/`No` still run the full pipeline, so semantics are unchanged.
+
+## 7. Frontend — first-page render for large folders
+
+`fetchFolderListing` paged the ENTIRE folder (sequential 200-item requests)
+before returning anything — a 2,000-item folder waited ~10 round-trips
+before first paint. The files route now paints page one immediately via the
+new `onPage` hook and fills in as later pages land (skipped when a cached
+listing is already on screen, so views never shrink). First-paint latency
+for an N-item folder drops from ⌈N/200⌉ sequential RTTs to 1.
+
+## Refuted by benchmark (reverted, kept for the record)
+
+- **Cached `Intl.Collator` for name sorts (frontend):** sorting 5,000 names —
+  argument-less `localeCompare` 5.6 ms vs cached collator **12.1 ms (2×
+  slower)**. V8 fast-paths argument-less `localeCompare`; the "cache the
+  collator" folklore does not apply. Reverted, ordering untouched.