perf: round 9 — decorator PUT reactivation, session/search/dedup alloc purges, PROPFIND join!, folder-level cascade

Benchmark-gated round (benches/ROUND9.md): every change carries a
BEFORE/AFTER bench with equivalence/safety gates; verdicts below are from
the committed harnesses on 4 cores / local PG 16.

Backend:
- Blob decorators (Retry/Cached) now forward put_blob_from_bytes_unsynced
  + sync_blobs — the trait default had silently reinstated HEAD-before-PUT
  per chunk on decorated remote stacks, undoing ROUND3 §8. Full production
  stack: 500 probes -> 0, 1.9x wall at 10 ms RTT (bench_s3_put §3).
- NC PROPFIND per-page enrichment triple (favorites / oc:fileid / dead
  props) overlapped with tokio::join!: 2.07x local, 2.86x at 5 ms RTT
  (bench_nc_enrich_join, injected-latency decide-by-bench).
- Search enrichment consumes its DTOs and carries the interned Arc<str>
  display fields end-to-end (SearchFileResultDto type change, OpenAPI
  shape preserved): enrich_file 2.0x, 11.6 -> 2.2 allocs/row; the NC
  REPORT conversion stops re-running all three classifiers per row
  (bench_search_enrich).
- NC session Arc end-to-end: SharedNcSession extractor (8 -> 0 allocs),
  Arc<FolderDto> chroot cache (4 -> 0/hit), single shared Arc<CurrentUser>
  + lazy span render (11 -> 6/build) (bench_nc_session).
- Storage micro-pack: atomic create_new chunk writes (2.1x fresh),
  stream_chunks over the manifest Arc (4097 -> 0 allocs/read incl. the
  Range path), manifest single-flight (herd 64 -> 1 loads), hex_lower for
  chunk Content-MD5 (18 -> 1 allocs) (bench_storage_micro).
- OCS capabilities memoized into OnceLock<[Bytes;2]>: 237x, 102 -> 0
  allocs/poll, byte-identical (bench_capabilities_static).
- Drive::is_empty COUNT(*) sum -> EXISTS: 34.4x on a 100k-file drive
  (bench_drive_is_empty).
- favorites/recents row-map ROUND7 port: path/name/blob_hash moved,
  -2.75 allocs/row (bench_resource_row_map §2).
- Folder rows decode binary UUIDs (ROUND6 §10 port): 1.03-1.07x page
  fetch, honest verdict incl. one noise-band wash documented
  (bench_folder_uuid_decode).
- Authz: file cascade decision decomposed into memoized folder-level
  decision + direct-grant lookup (ROUND8 deferred item). Cold shared-album
  first view 592 -> 418 µs/thumb; warm path unchanged; safety gates incl.
  new direct-grant sibling isolation, revoke-flush re-verified, full
  integration authz suite green (bench_thumbnail_cascade_cache).

Frontend (vitest gates committed beside the code):
- resolveLabel/resolveRecipient O(directory) scan -> id-keyed Map: 13.9x
  (recipients.bench.test.ts).
- ResourceList selection-prune effect skips when nothing is selected
  (100 -> 0 Set builds per drain) and the photos timeline reads a
  listener-fed mobile flag instead of matchMedia per recompute
  (listDerives.bench.test.ts).

Verification: cargo fmt + clippy --all-features --all-targets -D warnings
clean; 524 unit + 554 integration (--cfg integration_tests) tests pass;
frontend npm run check clean with 293 vitest tests green.

Deferred with rationale in ROUND9.md: CalDAV authz-before-fetch reorder
(maintainer sign-off), per-page batched parent resolution, JWT-claims
Arc<str>, batch_operations signature widening.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XDc9VtXvskJ6dnMRraSndn

src/interfaces/nextcloud/report_handler.rs

@@ -10,9 +10,7 @@ use quick_xml::{
 use std::collections::{HashMap, HashSet};
 use std::sync::Arc;
 
-use crate::application::dtos::display_helpers::{
-    category_for, format_file_size, icon_class_for, icon_special_class_for,
-};
+use crate::application::dtos::display_helpers::format_file_size;
 use crate::application::dtos::file_dto::FileDto;
 use crate::application::dtos::folder_dto::FolderDto;
 use crate::application::dtos::search_dto::SearchCriteriaDto;
@@ -401,15 +399,16 @@ fn file_dto_from_search(fr: &crate::application::dtos::search_dto::SearchFileRes
         name: fr.name.clone(),
         path: fr.path.clone(),
         size: fr.size,
-        mime_type: fr.mime_type.clone().into(),
+        // Interned `Arc<str>` carried through from enrichment — refcount
+        // bumps; the old code re-ran all three display classifiers and
+        // re-allocated each value per converted search row.
+        mime_type: fr.mime_type.clone(),
         folder_id: fr.folder_id.clone(),
         created_at: fr.created_at,
         modified_at: fr.modified_at,
-        icon_class: icon_class_for(&fr.name, &fr.mime_type).to_string().into(),
-        icon_special_class: icon_special_class_for(&fr.name, &fr.mime_type)
-            .to_string()
-            .into(),
-        category: category_for(&fr.name, &fr.mime_type).to_string().into(),
+        icon_class: fr.icon_class.clone(),
+        icon_special_class: fr.icon_special_class.clone(),
+        category: fr.category.clone(),
         size_formatted: format_file_size(fr.size),
         sort_date: None,
         content_hash: fr.blob_hash.clone(),
@@ -420,6 +419,16 @@ fn file_dto_from_search(fr: &crate::application::dtos::search_dto::SearchFileRes
     }
 }
 
+/// Bench-only public wrapper (feature = "bench") over the private
+/// search→FileDto conversion so `examples/bench_search_enrich.rs` can
+/// measure and equivalence-gate it.
+#[cfg(feature = "bench")]
+pub fn file_dto_from_search_for_bench(
+    fr: &crate::application::dtos::search_dto::SearchFileResultDto,
+) -> FileDto {
+    file_dto_from_search(fr)
+}
+
 /// Build a `FolderDto` from a search folder result.
 fn folder_dto_from_search(
     sr: &crate::application::dtos::search_dto::SearchFolderResultDto,