fix: isolate attachment submission state

.project-docs/30-worklog/tasks/20260823-pi-chat-timeline-c8f31a62.md

@@ -151,6 +151,14 @@
   behind a buffered continuous tail, Renderer requests one fresh target
   Snapshot; a repeated identical stale response becomes a retryable error
   instead of remaining in an infinite recovering state.
+- Closed the incremental planner review findings after `bec93d0`: attachment
+  editing is locked for the originating Conversation until upload and HTTP 202
+  acceptance settle, so removal or a next-message paste cannot mutate the
+  captured image set. Attachment preparation failures now remain local to the
+  Composer, restore the draft, permit direct retry without runtime recovery,
+  and retain already uploaded variants for reuse. Attachment route failures use
+  only registered `CODING_ATTACHMENT_INVALID`, `CODING_ATTACHMENT_NOT_FOUND`,
+  and `CODING_STORAGE_WRITE_FAILED` codes while preserving 413/404 status.
 - Synchronized `README.md` with the current Pi core Chat, first-Conversation,
   batch and attachment behavior. PI-130 feature controls and PI-140 legacy
   removal remain outside this task.
@@ -161,6 +169,10 @@
   **Standards Needs Fix / Spec Needs Fix**. PI-120 remained the unique Ready
   Frontier; the findings above were treated as blocking rather than advancing
   PI-130.
+- The correction candidate `bec93d0` received incremental planner review result
+  **Standards PASS / Spec Needs Fix**. Its three remaining attachment-state and
+  typed-error findings were implemented and kept PI-130 locked pending another
+  planner review.
 - Post-review focused suites passed: attachment Host routes, stale recovery,
   shared ProjectService/Registry mutation queue, slow Agent switch, cross-
   Conversation submission isolation, attachment count/concurrency and pressure
@@ -171,7 +183,11 @@
   20 React commits, 131,148 wire bytes, and measured Main-to-React p95
   `35.995 ms` against the `<=50 ms` budget. It includes mixed message blocks,
   4 KiB tool output and more than 100 KiB of cumulative thinking output.
-- `pnpm test`: passed, 218 files / 2316 passed / 2 skipped.
+- Latest attachment-state focused run passed: 3 files / 39 tests, including
+  delayed upload/removal, delayed HTTP 202/next-image isolation, local
+  preparation failure/direct retry, uploaded-variant reuse, and registered
+  Host error codes.
+- `pnpm test`: passed, 218 files / 2321 passed / 2 skipped.
 - `pnpm run typecheck`: passed.
 - `pnpm run lint:check`: passed with 0 errors and six unchanged warnings in
   `ExecutionGraphCard`, `Home`, and `Makelore`.