docs: record audited upload adapters

docs/superpowers/plans/2026-08-06-upload-collision-safety.md

@@ -4,7 +4,7 @@
 
 **Goal:** Make every DeerFlow upload ingress preserve same-name files under concurrent writes while isolating generated Markdown so conversion and deletion never overwrite or remove user uploads.
 
-**Architecture:** A shared upload manager stages complete payloads and publishes them with an atomic hard-link no-replace primitive, returning the actual `_N` filename. A focused layout module maps each primary upload to a system-owned `.upload-conversions/<full-primary-name>.md` asset, and a conversion wrapper publishes that asset atomically. Gateway, embedded client, generic IM, and DingTalk become transport adapters over these shared primitives.
+**Architecture:** A shared upload manager stages complete payloads and publishes them with an atomic hard-link no-replace primitive, returning the actual `_N` filename. A focused layout module maps each primary upload to a system-owned `.upload-conversions/<full-primary-name>.md` asset, and a conversion wrapper publishes that asset atomically. Gateway, embedded client, generic IM, Feishu, DingTalk, and WeChat download staging become transport adapters over these shared primitives.
 
 **Tech Stack:** Python 3.12+, pathlib/os/tempfile/shutil, asyncio, FastAPI/Pydantic, pytest/pytest-asyncio, unittest.mock, Ruff.
 
@@ -1135,11 +1135,11 @@ In DingTalk `_persist`, keep owner-scoped directory creation but replace the loc
 paths.ensure_thread_dirs(thread_id, user_id=effective_user_id)
 uploads_dir = paths.sandbox_uploads_dir(
     thread_id, user_id=effective_user_id
-).resolve()
+)
 return publish_upload_bytes(uploads_dir, safe_filename, content)
 ```
 
-Remove `_file_write_lock` because the shared primitive supplies cross-thread and cross-process correctness. Keep the other DingTalk locks. Build the returned path through `upload_virtual_path(resolved_target.name)`.
+Do not resolve the upload directory before publication: the shared publisher must inspect and reject a planted directory symlink itself. Remove `_file_write_lock` because the shared primitive supplies cross-thread and cross-process correctness. Keep the other DingTalk locks. Build the returned path through `upload_virtual_path(resolved_target.name)`.
 
 - [ ] **Step 5: Refresh the channel blocking-I/O regression descriptions**
 

docs/superpowers/specs/2026-08-06-upload-collision-safety-design.md

@@ -1,8 +1,8 @@
 # Upload Collision Safety Design
 
-**Issue:** #3750  
-**Status:** Approved in conversation; awaiting review of this written specification  
-**Scope:** Gateway uploads, embedded client uploads, inbound IM attachments, DingTalk attachments, generated Markdown conversions, outline lookup, and upload deletion
+**Issue:** #3750
+**Status:** Approved
+**Scope:** Gateway uploads, embedded client uploads, inbound IM attachments, generated Markdown conversions, outline lookup, and upload deletion
 
 ## Problem
 
@@ -100,7 +100,8 @@ request-local `seen_filenames` are removed from adapters rather than retained as
 naming mechanism.
 
 The publisher returns the actual filename chosen. Gateway, embedded client, generic IM,
-and DingTalk adapters all use it instead of implementing their own scan-then-write flow.
+Feishu, DingTalk, and WeChat download staging all use it instead of implementing their
+own scan-then-write flow.
 
 ## Conversion Publication and Ownership
 
@@ -152,10 +153,17 @@ layout as the Gateway. Repeated calls cannot overwrite an earlier upload.
 Downloaded attachment bytes are staged and published by the shared publisher. Correctness
 does not depend on a pre-download directory scan, so parallel messages are safe.
 
-### DingTalk
+### Feishu and DingTalk
 
-DingTalk uses the same publisher. Its in-process lock may remain for provider-specific
-coordination, but it is not relied on for cross-process or cross-adapter safety.
+Both direct-to-thread adapters use the same publisher and preserve the unresolved upload
+directory path so the publisher can reject a planted directory symlink. No process-local
+lock or pre-publication directory scan is relied on for correctness.
+
+### WeChat
+
+WeChat first downloads and decrypts inbound media into its channel state directory before
+the generic IM ingestion step. This temporary materialization also uses the publisher, so
+parallel messages cannot overwrite one another before the thread upload copy occurs.
 
 ### Sandbox synchronization
 
@@ -190,7 +198,7 @@ Tests are written before implementation and cover:
    deterministic unique names.
 2. Existing files and symlinks are never followed or replaced.
 3. Gateway uploads collide safely across separate and concurrent requests.
-4. Embedded, generic IM, and DingTalk ingress paths follow the same naming behavior.
+4. Embedded, generic IM, Feishu, DingTalk, and WeChat ingress paths follow the same naming behavior.
 5. Same-stem files with different extensions receive distinct conversion paths.
 6. A user-uploaded `report.md` is neither overwritten by converting `report.pdf` nor
    removed when `report.pdf` is deleted.