Security Panel MVP (#1660)

TODOs:

- [x] Add documentation
- [x] e2e tests: run security review, update knowledge, and fix issue
- [x] more stringent risk rating


<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Introduces a new Security mode with a Security Review panel that runs
reviews, edits rules, parses findings via IPC, and supports fixing
issues, with tests and prompt/runtime support.
> 
> - **UI/Preview Panel**:
> - Add `security` preview mode to `previewModeAtom` and ActionHeader
(Shield button).
> - New `SecurityPanel` showing findings table (sorted by severity), run
review, fix issue flow, and edit `SECURITY_RULES.md` dialog.
>   - Wire into `PreviewPanel` content switch.
> - **Hooks**:
>   - `useSecurityReview(appId)`: fetch latest review via IPC.
> - `useStreamChat`: add `onSettled` callback to invoke refreshes after
streams.
> - **IPC/Main**:
> - `security_handlers`: `get-latest-security-review` parses
`<dyad-security-finding>` from latest assistant message.
>   - Register handler in `ipc_host`; expose channel in `preload`.
>   - `ipc_client`: add `getLatestSecurityReview(appId)`.
> - `chat_stream_handlers`: detect `/security-review`, use dedicated
system prompt, optionally append `SECURITY_RULES.md`, suppress
Supabase-not-available note in this mode.
> - **Prompts**:
> - Add `SECURITY_REVIEW_SYSTEM_PROMPT` with structured finding output.
> - **Supabase**:
> - Enhance schema query to include `rls_enabled`, split policy
`using_clause`/`with_check_clause`.
> - **E2E Tests**:
> - New `security_review.spec.ts` plus snapshots and fixture findings;
update test helper for `security` mode and findings table snapshot.
> - Fake LLM server streams security findings for `/security-review` and
increases batch size.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
5022d01e22a2dd929a968eeba0da592e0aeece01. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

e2e-tests/security_review.spec.ts

@@ -0,0 +1,45 @@
+import { test, testSkipIfWindows } from "./helpers/test_helper";
+
+// Skipping because snapshotting the security findings table is not
+// consistent across platforms because different amounts of text
+// get ellipsis'd out.
+testSkipIfWindows("security review", async ({ po }) => {
+  await po.setUp({ autoApprove: true });
+  await po.sendPrompt("tc=1");
+
+  await po.selectPreviewMode("security");
+
+  await po.page
+    .getByRole("button", { name: "Run Security Review" })
+    .first()
+    .click();
+  await po.waitForChatCompletion();
+  await po.snapshotServerDump("all-messages");
+  await po.snapshotSecurityFindingsTable();
+
+  await po.page.getByRole("button", { name: "Fix Issue" }).first().click();
+  await po.waitForChatCompletion();
+  await po.snapshotMessages();
+});
+
+test("security review - edit and use knowledge", async ({ po }) => {
+  await po.setUp({ autoApprove: true });
+  await po.sendPrompt("tc=1");
+
+  await po.selectPreviewMode("security");
+  await po.page.getByRole("button", { name: "Edit Security Rules" }).click();
+  await po.page
+    .getByRole("textbox", { name: "# SECURITY_RULES.md\\n\\" })
+    .click();
+  await po.page
+    .getByRole("textbox", { name: "# SECURITY_RULES.md\\n\\" })
+    .fill("testing\nrules123");
+  await po.page.getByRole("button", { name: "Save" }).click();
+
+  await po.page
+    .getByRole("button", { name: "Run Security Review" })
+    .first()
+    .click();
+  await po.waitForChatCompletion();
+  await po.snapshotServerDump("all-messages");
+});