perf: keyset/LATERAL SQL shapes, auth+blob-cache single-flight, spool buffers, DTO interning

Round 3 of benchmark-gated optimizations (benches/ROUND3.md; every change
gated by a before/after benchmark — an AFTER that did not beat its BEFORE
was to be rolled back; none needed it. Equivalence gates assert identical
row sequences / byte-identical output on every behavior-preserving rewrite):

DB hot paths (local PG16, EXPLAIN-verified):
- Web-UI listing (list_resources_paged): cursor pushed INSIDE the
  folders/files UNION-ALL branches as sargable row-value comparisons with
  per-branch ORDER/LIMIT + two partial expression indexes
  (folder_id, LOWER(name), id). 20k-entry folder: 26.6 -> 1.3 ms/page
  (19.5x); other sort modes at parity or better. New migration
  20260918000000. [benches/LISTING-KEYSET.md section in ROUND3]
- Photos timeline (list_media_files): per-drive CROSS JOIN LATERAL top-N
  on the timeline index, joins moved above the top-N. 50k-photo library:
  97.4 -> 1.6 ms/page (55.7x). The old "LIMIT stops the scan early"
  comment was refuted by EXPLAIN.
- PROPFIND sub-folders (both DAV surfaces): keyset list_folders_batch off
  idx_folders_unique_name replaces COUNT(*) OVER() + LIMIT/OFFSET
  (5k dirs: 79.7 -> 17.9 ms full walk, 4.5x).

Concurrency:
- Basic-auth cache single-flight (moka try_get_with): 8 concurrent DAV
  connections at TTL expiry paid 8 Argon2id runs (2.6 s CPU + 8x64 MiB);
  now 1 (300 ms). Failed verifications remain uncached.
- CachedBlobBackend per-hash single-flight + unique tmp names: 16
  concurrent cold readers = 16 full remote downloads racing truncating
  writes on ONE deterministic .tmp (corruptible cache); now 1 download
  (16x less egress, 2.8x wall on a shared link) and torn files can never
  be renamed into the cache.

I/O and allocations:
- Chunk-assembly reads 64K -> 512K buffers (2.3x, 8x fewer syscalls);
  chunk-spool writes via BufWriter 512K (5.6x, 32x fewer syscalls).
- S3/Azure put_blob_from_bytes_unsynced overrides: dedup settle no longer
  pays a HEAD probe per new chunk (2 RTT -> 1, 1.8x); Azure stops copying
  every chunk (Bytes -> Body, -0.44 ms - 4 MiB alloc per 4 MiB chunk).
- Entity->DTO mapping: Arc<str> interning of closed-set display fields +
  common MIMEs, 1-alloc etag/size formatting, FolderDto moves instead of
  clones. File row: 11 -> 4 allocs; folder row: 11.8 -> 1 (2.1x faster).
- CardDAV REPORT: deleted dead per-contact vCard pre-generation and the
  O(N^2) uid scan whose result was discarded (5k contacts: 55.7 -> 5.7 ms,
  9.8x); byte-identical XML asserted.
- Search-results cache: byte weigher + 32 MiB budget
  (OXICLOUD_SEARCH_CACHE_MAX_BYTES) replaces the 1000-ENTRY cap that let
  ~300 MiB of enriched rows sit in RSS; read latency parity.
- Dropped aws-config + aws-smithy-types (zero references; -82 dep-graph
  nodes, three SDK stacks gone from every build). tokio "process" is now
  an explicit feature (was enabled transitively by aws-config).

Frontend:
- Cached Intl.DateTimeFormat keyed by (locale, options) in formatDate and
  4 sibling callsites: 20k dates 2612 -> 51 ms (51.6x); vitest gate
  asserts output identity across locales and a 3x floor.

Validation: cargo fmt + clippy --all-features --all-targets -D warnings
clean; 518 unit + 548 integration-cfg tests green; new-shape endpoints
smoke-tested end-to-end over HTTP (all 5 listing sort modes with cursor
walks, WebDAV PROPFIND Depth-1, photos timeline, Basic-auth DAV login);
frontend npm run check clean, new vitest gates green.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EBsU2qEzny3A8WQUEuMNCr

src/interfaces/upload_ingest.rs

@@ -273,11 +273,16 @@ pub fn multipart_field_stream(
 pub fn stream_from_files(
     paths: Vec<PathBuf>,
 ) -> impl Stream<Item = Result<Bytes, std::io::Error>> + Send {
+    // 512 KiB per poll: each ReaderStream poll on a tokio::fs::File is one
+    // blocking-pool dispatch + one read(2) of the buffer size. The old
+    // 64 KiB buffer paid 8x the dispatches/syscalls of every other blob
+    // read path (STREAM_CHUNK_SIZE = 256 KiB) for the single read pass
+    // over every completed chunked upload (benches/UPLOAD-SPOOL.md).
     stream::iter(paths.into_iter().map(Ok::<_, std::io::Error>))
         .and_then(|path| async move {
             tokio::fs::File::open(path)
                 .await
-                .map(|file| ReaderStream::with_capacity(file, 64 * 1024))
+                .map(|file| ReaderStream::with_capacity(file, 512 * 1024))
         })
         .try_flatten()
 }
@@ -319,9 +324,15 @@ pub async fn stream_body_to_path(
     max_bytes: usize,
     checksum_alg: Option<ChecksumAlg>,
 ) -> Result<StreamedToPath, AppError> {
-    let mut file = tokio::fs::File::create(path)
+    // BufWriter coalesces the per-HTTP-frame writes (~16-64 KiB each) into
+    // 512 KiB write(2)s — a bare tokio File dispatches one blocking-pool op
+    // per frame (benches/UPLOAD-SPOOL.md). Same capacity as the dedup
+    // handler's spool loop. On the error paths below the partial file is
+    // removed, so silently dropping unflushed buffer contents is fine.
+    let file = tokio::fs::File::create(path)
         .await
         .map_err(|e| AppError::internal_error(format!("Failed to open chunk file: {e}")))?;
+    let mut file = tokio::io::BufWriter::with_capacity(512 * 1024, file);
 
     let mut total_bytes: usize = 0;
     let mut stream = BodyStream::new(body);