Stream uploads directly into the CDC chunk store (no spool, single write)

Every upload surface previously wrote each byte to disk twice: the HTTP
body was spooled to a temp file (or assembled from chunk parts), then
mmap-re-read for FastCDC analysis, and finally the new chunks were
written to the blob backend. CDC could not start until the last byte
arrived, so large uploads paid receive + reread + rewrite latency.

The dedup engine now chunks, hashes and settles the stream WHILE it
arrives (fastcdc AsyncStreamCDC + incremental BLAKE3):

- Each batch of distinct chunks is pinned-or-classified by ONE
  `UPDATE … RETURNING` (no check-then-bump TOCTOU; pinned chunks can't
  be reclaimed mid-upload), and only chunks the store doesn't have are
  written — a full dedup hit performs zero content writes.
- Durability before visibility is preserved: one batched fsync sweep,
  then one batched INSERT, then the manifest. Identical concurrent
  uploads are resolved at the manifest INSERT via ON CONFLICT (the
  loser releases its references and becomes a dedup hit).
- A drop guard rolls back pins and surfaces written-but-unregistered
  chunks to GC if the request future is cancelled mid-stream.
- MIME sniffing now peeks the first bytes in-flight; client-requested
  MD5/SHA-256 checksums are computed by a stream tee — the post-upload
  re-read of the assembled file is gone.

All surfaces converge on the new interfaces::upload_ingest helper:
REST multipart, WebDAV PUT, NextCloud PUT, WOPI PutFile, the dedup
endpoint, and both chunked-upload completions (which now stream their
ordered parts straight into the store instead of writing an assembled
file — chunk parts persist until finalize, so completion is genuinely
retryable). The legacy blob re-chunk migration streams from the
backend with no spool file either.

Legacy removed: store_from_file + mmap CDC analysers + temp-path
plumbing through every port (pre_computed_hash, save_file_from_temp,
update_file_content_from_temp), upload_spool + assembled-file
assembly in both chunked services, create_file/update_file byte-slice
variants (no callers), common::temp, the OXICLOUD_UPLOAD_TMPDIR
config, and the memmap2 dependency.

Verified end-to-end against PostgreSQL 16: 8 MB upload (26 chunks),
identical re-upload (dedup hit, zero writes), 3-byte edit re-upload
(26 chunks, 1 written), byte-identical downloads, Range across chunk
boundaries, concurrent identical-upload race (manifest ref 2), and
trash-empty reclaiming exactly the unshared chunk while the shared 25
survive for the edited file. The empty/sub-8KB multipart path found a
post-EOF re-poll panic in the MIME peek (fixed with fuse + regression
test).

https://claude.ai/code/session_01WdNenpnujNR2sc32XVvwfS

src/application/ports/storage_ports.rs

@@ -251,21 +251,21 @@ pub struct CopyFolderTreeResult {
 
 /// Secondary port for file **writing**.
 ///
-/// Covers: upload (buffered + streaming), move, delete, update,
-/// and deferred registration for the write-behind cache.
+/// Covers: upload registration, move, delete, update, and deferred
+/// registration for the write-behind cache.
 pub trait FileWritePort: Send + Sync + 'static {
-    /// Streaming upload — saves a file from a temp file already on disk.
+    /// Register a file row pointing at a blob already stored in the
+    /// content-addressable chunk store.
     ///
-    /// When `pre_computed_hash` is provided, the dedup service skips the
-    /// hash re-read — zero extra I/O beyond the initial spool.
-    async fn save_file_from_temp(
+    /// Takes ownership of one blob reference: on any failure the reference
+    /// is released before the error is returned.
+    async fn save_file_with_blob(
         &self,
         name: String,
         folder_id: Option<String>,
         content_type: String,
-        temp_path: &std::path::Path,
+        blob_hash: &str,
         size: u64,
-        pre_computed_hash: Option<String>,
     ) -> Result<File, DomainError>;
 
     /// Moves a file to another folder.
@@ -281,22 +281,20 @@ pub trait FileWritePort: Send + Sync + 'static {
     /// Deletes a file.
     async fn delete_file(&self, id: &str) -> Result<(), DomainError>;
 
-    /// Streaming update — replaces file content from a temp file on disk.
+    /// Atomically swap a file's content to a blob already stored in the
+    /// content-addressable chunk store.
     ///
-    /// When `pre_computed_hash` is provided, the dedup service skips the
-    /// hash re-read — zero extra I/O beyond the initial spool.
-    /// Peak RAM: ~256 KB regardless of file size.
+    /// Takes ownership of one blob reference (released on failure); the
+    /// previous content's reference is dropped after the swap.
     ///
     /// Returns `(new_blob_hash, updated_at_epoch)` — everything a caller
     /// needs to rebuild the fresh entity/ETag from a `File` it already
     /// holds, without re-reading the row it just updated.
-    async fn update_file_content_from_temp(
+    async fn update_file_content_with_blob(
         &self,
         file_id: &str,
-        temp_path: &std::path::Path,
+        blob_hash: &str,
         size: u64,
-        content_type: Option<String>,
-        pre_computed_hash: Option<String>,
         modified_at: Option<i64>,
     ) -> Result<(String, i64), DomainError>;