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 -->

testing/fake-llm-server/chatCompletionHandler.ts

@@ -143,6 +143,7 @@ export default Index;
         "\n\n" +
         generateDump(req);
     }
+
     console.error("LASTMESSAGE", lastMessage);
     // Check if the last message is "[dump]" to write messages to file and return path
     if (
@@ -157,6 +158,27 @@ export default Index;
       messageContent = generateDump(req);
     }
 
+    if (
+      lastMessage &&
+      typeof lastMessage.content === "string" &&
+      lastMessage.content.startsWith("/security-review")
+    ) {
+      messageContent = fs.readFileSync(
+        path.join(
+          __dirname,
+          "..",
+          "..",
+          "..",
+          "e2e-tests",
+          "fixtures",
+          "security-review",
+          "findings.md",
+        ),
+        "utf-8",
+      );
+      messageContent += "\n\n" + generateDump(req);
+    }
+
     if (lastMessage && lastMessage.content === "[increment]") {
       globalCounter++;
       messageContent = `counter=${globalCounter}`;
@@ -335,7 +357,7 @@ export default Index;
 
     // Stream each character with a delay
     let index = 0;
-    const batchSize = 8;
+    const batchSize = 32;
 
     // Send role first
     res.write(createStreamChunk("", "assistant"));