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

Cargo.toml

@@ -350,6 +350,57 @@ name = "bench_micro_allocs"
 path = "examples/bench_micro_allocs.rs"
 required-features = ["bench"]
 
+# Round-9 battery ─────────────────────────────────────────────────────────────
+
+# Search enrichment — borrow+clone+reclassify vs consume+carry (file/folder
+# enrich + the NC REPORT search→FileDto conversion). No Postgres.
+[[example]]
+name = "bench_search_enrich"
+path = "examples/bench_search_enrich.rs"
+required-features = ["bench"]
+
+# Storage micro-pack — local chunk write create_new, manifest Vec-clone vs
+# Arc-index, manifest miss single-flight, Content-MD5 hex. No Postgres.
+[[example]]
+name = "bench_storage_micro"
+path = "examples/bench_storage_micro.rs"
+required-features = ["bench"]
+
+# NC per-request session — extractor deep-clone vs Arc handle, chroot-cache
+# value vs Arc, session build double-clone vs shared Arc. No Postgres.
+[[example]]
+name = "bench_nc_session"
+path = "examples/bench_nc_session.rs"
+required-features = ["bench"]
+
+# OCS capabilities poll — rebuild+serialize per request vs OnceLock<Bytes>
+# memoization. No Postgres.
+[[example]]
+name = "bench_capabilities_static"
+path = "examples/bench_capabilities_static.rs"
+required-features = ["bench"]
+
+# Drive::is_empty — full-drive COUNT(*) sum vs short-circuit EXISTS
+# (needs the dev Postgres up).
+[[example]]
+name = "bench_drive_is_empty"
+path = "examples/bench_drive_is_empty.rs"
+required-features = ["bench"]
+
+# Folder-listing rows — `id::text`/`parent_id::text` casts vs binary UUID
+# decode + app-side render, the round-6 file-side port (needs Postgres).
+[[example]]
+name = "bench_folder_uuid_decode"
+path = "examples/bench_folder_uuid_decode.rs"
+required-features = ["bench"]
+
+# NC PROPFIND per-page enrichment triple — serial 3×RTT vs tokio::join!,
+# with injected-latency arms at 0/0.25/1/5 ms (needs Postgres).
+[[example]]
+name = "bench_nc_enrich_join"
+path = "examples/bench_nc_enrich_join.rs"
+required-features = ["bench"]
+
 # Round-8 battery ─────────────────────────────────────────────────────────────
 
 # Shared-album thumbnail authz — folder-grant cascade query per thumbnail vs