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/common/stubs.rs

@@ -193,6 +193,17 @@ impl FileWritePort for StubFileWritePort {
         Ok(())
     }
 
+    async fn update_file_content_from_temp(
+        &self,
+        _file_id: &str,
+        _temp_path: &Path,
+        _size: u64,
+        _content_type: Option<String>,
+        _pre_computed_hash: Option<String>,
+    ) -> Result<(), DomainError> {
+        Ok(())
+    }
+
     async fn register_file_deferred(
         &self,
         _name: String,
@@ -485,6 +496,17 @@ impl FileUploadUseCase for StubFileUploadUseCase {
     async fn update_file(&self, _path: &str, _content: &[u8]) -> Result<(), DomainError> {
         Ok(())
     }
+
+    async fn update_file_streaming(
+        &self,
+        _path: &str,
+        _temp_path: &Path,
+        _size: u64,
+        _content_type: &str,
+        _pre_computed_hash: Option<String>,
+    ) -> Result<(), DomainError> {
+        Ok(())
+    }
 }
 
 // ---------------------------------------------------------------------------