fix(desktop): wait for terminal frame before splash (#4781)

## Summary

- keep the first-open Buzz Term splash pending until the active PTY
delivers its first frame
- retrigger the splash effect when that readiness gate changes
- cover the real bootstrap path so startup latency cannot consume the
animation invisibly

## Verification

- Wes manually verified the first-open animation in the worktree
- `pnpm --dir desktop typecheck`
- `pnpm --dir desktop test` — 4,195 passed
- `pnpm exec biome check src/features/terminal/TerminalBootstrap.tsx
src/features/terminal/TerminalSubstrate.tsx
src/features/terminal/TerminalBootstrap.test.mjs`
- pre-push hooks — branch skew, desktop check, and 4,195 desktop tests
passed

The repository-wide `pnpm --dir desktop check` still reports
pre-existing diagnostics in `personaCatalogRelay.test.mjs` and
`terminal.css`; the three changed files pass Biome directly.

Signed-off-by: Wes <wesbillman@users.noreply.github.com>
Co-authored-by: Carl <c7ebe626f000404285d3686e1dc74cc07cc60a9754a150041ba132e14bd3e2ec@buzz.block.builderlab.xyz>

desktop/src/features/terminal/TerminalBootstrap.test.mjs

@@ -234,6 +234,56 @@ test("mounted bootstrap passes GUI context and ACKs only after consuming a frame
   );
   view.unmount();
 });
+
+test("first-open splash waits for the first terminal frame", async () => {
+  const { createElement } = await import("react");
+  const { act, render, waitFor } = await import("@testing-library/react");
+  const { ThemeProvider } = await import("@/shared/theme/ThemeProvider");
+  const { TerminalBootstrap } = await import("./TerminalBootstrap.tsx");
+
+  const view = render(
+    createElement(
+      ThemeProvider,
+      null,
+      createElement(TerminalBootstrap, {
+        channelId: "channel-1",
+        channelName: "general",
+        npub: "npub1owner",
+        relayUrl: "wss://relay.example",
+        threadId: null,
+      }),
+    ),
+  );
+  await waitFor(() =>
+    assert.ok(calls.some(({ command }) => command === "terminal_attach")),
+  );
+  assert.equal(
+    view.container.querySelector(".buzz-terminal-welcome"),
+    null,
+    "the splash must not be consumed while the first PTY frame is pending",
+  );
+
+  await act(async () => {
+    emit({
+      type: "frame",
+      payload: {
+        bracketedPaste: false,
+        cursor: { column: 0, line: 0, visible: true },
+        focusReporting: false,
+        full: true,
+        rows: [],
+        sequence: 1,
+        subscriptionId: "subscription-1",
+        viewport: { columns: 100, generation: 0, screenLines: 24 },
+      },
+    });
+  });
+  await waitFor(() =>
+    assert.ok(view.container.querySelector(".buzz-terminal-welcome")),
+  );
+  view.unmount();
+});
+
 test("resize during in-flight catch-up keeps the newest viewport ready", async () => {
   const { createElement } = await import("react");
   const { act, render, waitFor } = await import("@testing-library/react");

desktop/src/features/terminal/TerminalBootstrap.tsx

@@ -371,7 +371,7 @@ export function TerminalBootstrap({
       focusReportingEnabled={active?.frame?.focusReporting ?? false}
       frame={active?.frame}
       viewportReportingEnabled={viewportReportingEnabled}
-      showSplash={splashPending}
+      showSplash={splashPending && Boolean(active?.frame)}
       onSplashStarted={handleSplashStarted}
       sessionFrames={channelSessions.flatMap((session) =>
         session.frame ? [{ sessionId: session.key, frame: session.frame }] : [],

desktop/src/features/terminal/TerminalSubstrate.tsx

@@ -345,8 +345,9 @@ export function TerminalSubstrate({
       setWelcomeVisible(false);
       return;
     }
-    if (!viewportReportingEnabled || !banner || !beginSplash()) return;
-  }, [banner, viewportReportingEnabled, visible]);
+    if (!showSplash || !viewportReportingEnabled || !banner || !beginSplash())
+      return;
+  }, [banner, showSplash, viewportReportingEnabled, visible]);
 
   React.useEffect(() => {
     if (!welcomeVisible) return;