fix: OOM protection, lock-free thumbnail cache, OIDC JWKS TTL

- Streaming WebDAV PUT: body spooled to tempfile with incremental SHA-256,
  peak RAM ~64KB regardless of file size (Solution 2)
- RequestBodyLimitLayer (1MB) on CalDAV/CardDAV routers (Solution 3)
- All body::to_bytes(body, usize::MAX) replaced with explicit limits:
  PROPFIND/PROPPATCH/LOCK → 1MB, MKCOL → 4KB
- Added AppError::payload_too_large (HTTP 413)
- Added max_upload_size to StorageConfig (default 10GB, env override)
- New streaming update chain: FileWritePort::update_file_content_from_temp
  → FileUploadUseCase::update_file_streaming
- ThumbnailService: migrated from RwLock<LruCache> to moka::future::Cache
  with weight-based eviction — eliminates lock contention on read hot-path
- OIDC: discovery + JWKS caches now expire after 1 hour (Cached<T> wrapper)
  so IdP key rotation no longer requires server restart

src/application/ports/file_ports.rs

@@ -70,6 +70,20 @@ pub trait FileUploadUseCase: Send + Sync + 'static {
 
     /// Updates the content of an existing file (for WebDAV)
     async fn update_file(&self, path: &str, content: &[u8]) -> Result<(), DomainError>;
+
+    /// Streaming update — spools body to a temp file with incremental hash,
+    /// then atomically replaces the file content via dedup store.
+    ///
+    /// Peak RAM: ~256 KB regardless of file size.
+    /// Used by WebDAV PUT for large files.
+    async fn update_file_streaming(
+        &self,
+        path: &str,
+        temp_path: &Path,
+        size: u64,
+        content_type: &str,
+        pre_computed_hash: Option<String>,
+    ) -> Result<(), DomainError>;
 }
 
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