See #1692

<!-- CURSOR_SUMMARY -->
> [!NOTE]
> Adds multi-select with a "Fix X Issues" bulk action to Security Review
(severity-sorted, with animated header button), clears selections on
refresh, and improves streaming error logs; includes e2e coverage.
> 
> - **Security Review UI
(`src/components/preview_panel/SecurityPanel.tsx`)**:
>   - **Multi-select & Bulk Fix**:
> - Add per-row checkboxes and a "Select all" checkbox in
`FindingsTable`; sort by severity; ARIA labels.
> - Track `selectedFindings`; clear on new data; header shows animated
"Fix X Issues" button (`Wrench` icon) that creates one chat with a
combined prompt for selected issues.
> - **Fix Single Issue**: Preserve existing per-row "Fix Issue" flow
with loading states.
> - **Tests**:
> - Add e2e test `security review - multi-select and fix issues` and
snapshots for selection table and combined prompt.
> - **IPC (`src/ipc/ipc_client.ts`)**:
> - Enhance error logging (`console.error`) in `streamMessage` paths;
simplify `cancelChatStream` (remove stale cleanup).
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
08b9f92814e2a676d0a8de1badf7dc79cd82a14a. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->



<!-- This is an auto-generated description by cubic. -->
---
## Summary by cubic
Add multi-select to the Security Review so you can select issues and fix
them in one go. Improves error handling in chat streaming and adds an
e2e test for the new flow.

- New Features
- Checkboxes per finding and a “Select all” checkbox, with
severity-sorted rows.
- Header shows an animated “Fix X Issues” button when items are
selected; creates one chat with a combined prompt; clears selection
after.
  - New e2e test: multi-select and bulk fix.

- Bug Fixes
  - Clear selections when new review results load.
- Better error logging in IpcClient for streaming failures; simplify
cancelChatStream to avoid false errors.

<sup>Written for commit 08b9f92814e2a676d0a8de1badf7dc79cd82a14a.
Summary will update automatically on new commits.</sup>

<!-- End of auto-generated description by cubic. -->