feat(applications): preserve submitted packages

docs/architecture/application-workspace.md

@@ -14,7 +14,9 @@ application's home.
 
 ## What it is NOT
 
-The workspace **owns no data and duplicates none**. It is an aggregate read plus a navigation shell:
+The workspace normally composes existing data. Its one deliberate ownership boundary is an
+append-only submitted-package snapshot: immutable evidence must duplicate what was sent so later
+profile, CV, cover-letter, and attachment edits cannot rewrite history.
 
 | Section | Backed by (existing system) |
 |---|---|
@@ -26,12 +28,13 @@ The workspace **owns no data and duplicates none**. It is an aggregate read plus
 | Application answers / recruiter draft | compatibility fields on `JobApplication`, exposed as separate workspace fields |
 | Analysis / Match / Interview | Phase 5 `AiWorkspacePanel` + `AiInteraction` history |
 | Documents | `Attachment` |
+| Submitted package history | `SubmittedApplicationPackage` + copied, SHA-256-identified attachment bytes |
 | Communication | `Correspondence` |
 | Activity / Timeline | `JobEvent` |
 | Stage semantics | `JobPipeline` |
 
-No career data is copied into the application. Nothing in this feature writes to the master profile,
-a CV variant, or a cover letter.
+Nothing in this feature writes back to the master profile, a CV variant, or a cover letter. A user-
+initiated submission snapshot copies their current values into an append-only evidence record.
 
 ## Backend
 
@@ -234,6 +237,19 @@ With no profile it returns score 0 and asks the user to build one, rather than i
 
 ## Application assets (Phase 5.4)
 
+### Submitted application packages
+
+`POST /api/jobapplications/{id}/submitted-packages` freezes the current package without mutating its
+sources. It records the exact career-profile JSON, variant settings/version, rendered CV HTML,
+cover-letter text, application drafts/notes, opportunity context, and independent copies of every
+live attachment. Each copied file has its own SHA-256 digest and remains downloadable from the
+package even when the live attachment is later renamed, replaced, or deleted.
+
+Packages are append-only and numbered per application. There is no update or delete endpoint.
+List/detail/download routes are tenant-scoped, and account export/deletion includes both snapshot
+metadata and bytes. Capture fails as a unit if any selected attachment is unavailable; it never
+creates a package that silently omits a file.
+
 The workspace becomes the place an application is prepared. The rule is one-directional:
 
 ```