Merge origin SMB fixes with local Phase 21-22 features

Origin changes merged:
- SMB performance optimization (pread/pwrite, tokio Mutex)
- macOS SMB mount fix (AAPL caps, credit grant)
- Compound request integration tests
- CTDB architecture analysis

Local changes preserved:
- upload_path config (deployed, tested stable)
- delete_file + preview_file routes (MyFiles UI)
- SSH async I/O (cipher.rs, packet.rs, server.rs)
- auth.sqlite (86016 bytes, important user data)
- Admin WebDAV + CorsLayer
- api/admin.rs + api/config.rs (new endpoints)

Conflicts resolved:
- myfiles.rs: kept upload_path + OnceLock static
- auth.sqlite: preserved local version (important data)

Test results: 393 passed, 5 auth tests failed
- PG tests require external PostgreSQL
- Auth tests expect specific password hashes
- auth.sqlite preserved with actual user credentials

Cargo.lock

@@ -3055,6 +3055,7 @@ dependencies = [
  "tokio-postgres",
  "tokio-util",
  "toml",
+ "tower-http 0.5.2",
  "tracing",
  "tracing-subscriber",
  "unrar",
@@ -4633,7 +4634,7 @@ dependencies = [
  "tokio",
  "tokio-native-tls",
  "tower",
- "tower-http",
+ "tower-http 0.6.11",
  "tower-service",
  "url",
  "wasm-bindgen",
@@ -6117,6 +6118,22 @@ dependencies = [
  "tracing",
 ]
 
+[[package]]
+name = "tower-http"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e9cd434a998747dd2c4276bc96ee2e0c7a2eadf3cae88e52be55a05fa9053f5"
+dependencies = [
+ "bitflags 2.11.1",
+ "bytes",
+ "http",
+ "http-body",
+ "http-body-util",
+ "pin-project-lite",
+ "tower-layer",
+ "tower-service",
+]
+
 [[package]]
 name = "tower-http"
 version = "0.6.11"