[codex] Refresh issue documents from live updates (#6005)

## Thinking Path

> - Paperclip orchestrates AI agents for zero-human companies.
> - The board UI keeps issue pages responsive by subscribing to live
activity events and invalidating TanStack Query caches.
> - Issue documents are first-class issue artifacts, but document
activity events were not refreshing the document list, active document,
or revision caches.
> - That meant a user could update a document on an issue and another
open board would keep showing stale document content until a page
reload.
> - This pull request routes issue document activity events through the
same live invalidation path used for issue and comment updates.
> - The benefit is that issue document changes become visible
automatically on active issue pages without forcing operators to reload
the board.

## What Changed

- Added live-update cache invalidation for `issue.document_created`,
`issue.document_updated`, `issue.document_restored`, and
`issue.document_deleted` activity events.
- Invalidated the issue document list, the active document cache, and
document revisions for both issue id and identifier references when the
activity payload includes a document key.
- Added regression coverage for document activity events so active issue
pages refetch document caches without inactive-only behavior.
- Simplified the document invalidation test mock after Greptile feedback
so the test only models the cache reads it actually uses.

## Verification

- `git rebase public-gh/master` reported the branch was up to date after
fetching `public-gh/master`.
- `pnpm run preflight:workspace-links` passed.
- `pnpm exec vitest run --project @paperclipai/ui
ui/src/context/LiveUpdatesProvider.test.ts` passed: 1 file, 16 tests.
- `pnpm --filter @paperclipai/ui typecheck` passed.
- PR checks passed on `eecd19f7b0355490f17314c94bffa06aada8f9e3`:
`policy`, `verify`, `e2e`, all 4 serialized server shards, `Canary Dry
Run`, `security/snyk`, and `Greptile Review`.
- Greptile completed with `5/5` confidence and no unresolved review
threads.

## Risks

- Low risk. This expands cache invalidation for existing live activity
events and does not change API contracts, database schema, migrations,
or document persistence behavior.
- No migrations or `pnpm-lock.yaml` changes are included.

> For core feature work, check [`ROADMAP.md`](ROADMAP.md) first and
discuss it in `#dev` before opening the PR. Feature PRs that overlap
with planned core work may need to be redirected — check the roadmap
first. See `CONTRIBUTING.md`.

## Model Used

- OpenAI Codex, GPT-5 coding agent, tool-enabled local repository
workflow.

## Checklist

- [x] I have included a thinking path that traces from project context
to this change
- [x] I have specified the model used (with version and capability
details)
- [x] I have checked ROADMAP.md and confirmed this PR does not duplicate
planned core work
- [x] I have run tests locally and they pass
- [x] I have added or updated tests where applicable
- [x] No visible UI layout changed; screenshots are not applicable for
live cache invalidation behavior
- [x] No documentation changes were needed for this internal UI cache
refresh fix
- [x] I have considered and documented any risks above
- [x] I will address all Greptile and reviewer comments before
requesting merge

---------

Co-authored-by: Paperclip <noreply@paperclip.ing>

ui/src/context/LiveUpdatesProvider.tsx

@@ -408,6 +408,12 @@ async function hydrateVisibleIssueComment(
 }
 
 const ISSUE_TOAST_ACTIONS = new Set(["issue.created", "issue.updated", "issue.comment_added"]);
+const ISSUE_DOCUMENT_ACTIVITY_ACTIONS = new Set([
+  "issue.document_created",
+  "issue.document_updated",
+  "issue.document_restored",
+  "issue.document_deleted",
+]);
 const AGENT_TOAST_STATUSES = new Set(["error"]);
 const RUN_TOAST_STATUSES = new Set(["failed", "timed_out", "cancelled"]);
 
@@ -685,6 +691,17 @@ function invalidateActivityQueries(
         if (action === "issue.comment_added") {
           queryClient.invalidateQueries({ queryKey: queryKeys.issues.comments(ref), ...invalidationOptions });
         }
+        if (action && ISSUE_DOCUMENT_ACTIVITY_ACTIONS.has(action)) {
+          const documentKey = readString(details?.key);
+          queryClient.invalidateQueries({ queryKey: queryKeys.issues.documents(ref), ...invalidationOptions });
+          if (documentKey) {
+            queryClient.invalidateQueries({ queryKey: queryKeys.issues.document(ref, documentKey), ...invalidationOptions });
+            queryClient.invalidateQueries({ queryKey: queryKeys.issues.documentRevisions(ref, documentKey), ...invalidationOptions });
+          } else {
+            queryClient.invalidateQueries({ queryKey: ["issues", "document", ref], ...invalidationOptions });
+            queryClient.invalidateQueries({ queryKey: ["issues", "document-revisions", ref], ...invalidationOptions });
+          }
+        }
         if (action?.startsWith("issue.thread_interaction_")) {
           queryClient.invalidateQueries({ queryKey: queryKeys.issues.interactions(ref), ...invalidationOptions });
         }