feat(wasm-viewer): restore Load Parquet upload affordance (#923)

The static-site WASM viewer's landing page exposed only Demos and Load
URL — the dropzone wasn't wired (no `onFile` handler) and the topnav
"Load Parquet" button never showed up after a capture loaded
(initDashboard was called without `onUploadParquet`). Both surfaces
work in the server viewer; the WASM bootstrap was just missing the
glue.

Add a single `loadFile(file)` helper in `site/viewer/lib/script.js`
that reads the File's bytes and runs the existing `loadParquet`
flow. Pass it as `onFile` on the FileUpload landing component AND as
`onUploadParquet` into `initDashboard`, so the same handler powers
the dropzone, the landing's Choose-File button, and the topnav button
once a capture is loaded. Drops `?demo` / `?capture` URL params on
upload so a refresh doesn't fight the just-uploaded file.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: thinkingfish

Cargo.lock

@@ -27,7 +27,7 @@ wasm-bindgen = "0.2.120"
 
 [package]
 name = "rezolus"
-version = "5.13.1-alpha.5"
+version = "5.13.1-alpha.6"
 description = "High resolution systems performance telemetry agent"
 edition = "2021"
 license.workspace = true

Cargo.toml

@@ -124,9 +124,47 @@ async function loadParquet(data, filename) {
         fileMetadata: state.fileMetadata,
         selectionPayload: state.selectionPayload,
         reportMode,
+        // Wire the topnav "Load Parquet" button to the same handler the
+        // landing-page dropzone uses. The server viewer uploads via
+        // /api/v1/upload; here we take the File bytes and reuse
+        // loadParquet directly.
+        onUploadParquet: loadFile,
     });
 }
 
+// Shared file-upload entry point: reads the File's bytes and runs the
+// usual loadParquet flow. Used by both the landing-page Choose-File /
+// drop zone and the topnav "Load Parquet" button after a capture is
+// already loaded (which destroys the splash and re-enters loadParquet
+// with the new bytes — same lifecycle as `loadCapture`).
+async function loadFile(file) {
+    if (!file) return;
+    const display = file.name || 'capture.parquet';
+    splashLabel = display;
+    splashProgress = -1;
+    landingError = null;
+    m.redraw();
+    try {
+        const data = new Uint8Array(await file.arrayBuffer());
+        splashLabel = 'Initializing';
+        splashProgress = -1;
+        m.redraw();
+        await loadParquet(data, display);
+        // Drop any URL params that pinned the previous capture so a
+        // refresh doesn't fight the just-uploaded file.
+        const url = new URL(window.location);
+        url.searchParams.delete('demo');
+        url.searchParams.delete('demoA');
+        url.searchParams.delete('demoB');
+        url.searchParams.delete('capture');
+        window.history.replaceState(null, '', url);
+    } catch (e) {
+        splashLabel = null;
+        landingError = `Failed to load ${display}: ${e?.message ?? e ?? 'unknown error'}`;
+        m.redraw();
+    }
+}
+
 // ── Load demo parquet (with download progress) ──────────────────────
 
 // Fetch a parquet by URL or relative path. Relative paths resolve under
@@ -383,6 +421,7 @@ const Root = {
             ]));
         }
         return m('div', m(FileUpload, {
+            onFile: loadFile,
             onDemo: (demo) => {
                 if (demo && Array.isArray(demo.files) && demo.files.length === 2) {
                     loadCompareDemo(