fix: upload progress was rebuilding the whole media panel per tick

The previous fix (67b1324) put mediaUpload straight into the mediabrowser
zone's fingerprint, so every XHR progress tick did a full rebuild of the
media grid, thumbnails, and project list -- and closed any open <select>
in there (e.g. "Sort by"), the same class of bug just fixed in Engine
settings. Only the file boundary (which file, 1-of-how-many) is in the
fingerprint now; byte-level progress goes through a quiet
updateMediaUploadProgress + a funpack-media-upload-progress event that
mediabrowser.js uses to patch the bar/percent in place, mirroring the
existing updateGenProgress/funpack-gen-progress pattern for the player.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

movie_editor/frontend/mediabrowser.js

@@ -17,6 +17,19 @@
     for (const id of thumbCache.keys()) if (!ids.has(id)) thumbCache.delete(id);
   }
 
+  // Drop-zone upload bar, patched in place on funpack-media-upload-progress (below) instead
+  // of rebuilding — a full render only happens once per file, at the fpMediabrowser fingerprint
+  // in view_bus.js's granularity (see mediaTab). Cleared whenever the zone isn't currently the
+  // "uploading" one, so a stale reference from a since-discarded render never gets written to.
+  let _uploadFillEl = null, _uploadPctEl = null;
+  window.addEventListener("funpack-media-upload-progress", (e) => {
+    if (!_uploadFillEl || !_uploadFillEl.isConnected) return;
+    const up = (e && e.detail) || {};
+    const pct = up.size > 0 ? Math.min(100, Math.round((up.loaded / up.size) * 100)) : null;
+    _uploadFillEl.style.width = (pct == null ? 0 : pct) + "%";
+    if (_uploadPctEl) _uploadPctEl.textContent = pct == null ? "uploading…" : `${pct}%`;
+  });
+
   const mediaSelected = new Set();   // media bin multi-select
   let mediaSelectMode = false;     // when off, click = preview; when on, click = toggle selection
   const MF_KEY = "fp_media_filter";
@@ -473,8 +486,13 @@
       bar.style.width = (pct == null ? 0 : pct) + "%";
       barWrap.append(bar);
       drop.append(barWrap);
-      drop.append(el("div", "pj-meta", pct == null ? "uploading…" : `${pct}%`));
+      const pctEl = el("div", "pj-meta", pct == null ? "uploading…" : `${pct}%`);
+      drop.append(pctEl);
+      // Live-patched by the funpack-media-upload-progress listener above for every tick
+      // within this file — this render only happens once per file (see fpMediabrowser).
+      _uploadFillEl = bar; _uploadPctEl = pctEl;
     } else {
+      _uploadFillEl = null; _uploadPctEl = null;
       drop.append(el("div", "big", "🎞"));
       drop.append(el("div", null, "Drop images, video & audio here"));
       drop.append(el("div", "pj-meta", "or click to browse · drag onto a clip to set its anchor"));

movie_editor/frontend/store.js

@@ -211,6 +211,16 @@
     Object.assign(state.gen, patch);
     try { window.dispatchEvent(new CustomEvent("funpack-gen-progress", { detail: state.gen })); } catch (_) {}
   }
+
+  // Same idea as updateGenProgress: XHR upload progress fires many times a second, and a
+  // full notify() would rebuild the whole media bin (thumbnails, project list, any open
+  // <select>) on every tick. Mutate quietly and let mediabrowser.js patch its own bar/percent
+  // in place instead.
+  function updateMediaUploadProgress(patch) {
+    if (!state.mediaUpload) return;
+    Object.assign(state.mediaUpload, patch);
+    try { window.dispatchEvent(new CustomEvent("funpack-media-upload-progress", { detail: state.mediaUpload })); } catch (_) {}
+  }
   function get() { return state; }
 
   function _promptPreviewKey(project) {
@@ -4427,19 +4437,15 @@
   // uploading over a slow connection just looked like nothing was happening.
   async function uploadMedia(files) {
     const list = [...files];
-    let lastNotify = 0;
     for (let i = 0; i < list.length; i++) {
       const f = list[i];
+      // A full notify() here (once per file) is what builds the "uploading" drop zone in the
+      // first place -- see fpMediabrowser in view_bus.js. Progress WITHIN a file goes through
+      // updateMediaUploadProgress instead, which never touches the store's subscribers.
       set({ mediaUpload: { current: i + 1, total: list.length, name: f.name, loaded: 0, size: f.size } });
-      lastNotify = Date.now();
       try {
         await API.uploadMedia(f, (loaded, total) => {
-          state.mediaUpload = { ...state.mediaUpload, loaded, size: total || f.size };
-          // XHR fires this many times a second -- notify() rebuilds the whole media grid,
-          // so this throttles to a still-smooth ~8fps instead of hammering a full re-render
-          // on every tick. The final `loaded === total` (upload done) always gets through.
-          const now = Date.now();
-          if (now - lastNotify >= 120 || loaded >= total) { lastNotify = now; notify(); }
+          updateMediaUploadProgress({ loaded, size: total || f.size });
         });
       } catch (e) { console.error("upload failed", e); }
     }

movie_editor/frontend/view_bus.js

@@ -176,10 +176,15 @@
       projects: st.projects?.length,
       media: st.mediaBin?.length,
       mediaPreview: st.mediaPreviewId,
-      // The upload progress bar/percent live in this zone and change on every XHR
-      // progress tick without touching mediaBin's length -- without this the drop
-      // zone never repaints and looks stale for the whole upload.
-      upload: st.mediaUpload,
+      // Only the file boundary (which file, 1-of-how-many) belongs in the fingerprint --
+      // that's rare enough to justify a full rebuild, which is what creates the "uploading"
+      // drop zone in the first place. `loaded` ticks many times a second and is deliberately
+      // left out: a full rebuild on every tick would tear down and rebuild the whole bin
+      // (thumbs, project list, any open <select> like "Sort by"). See the
+      // funpack-media-upload-progress listener in mediabrowser.js, which patches the drop
+      // zone's bar/percent in place instead, the same way funpack-gen-progress does for the
+      // player's readout.
+      upload: st.mediaUpload ? `${st.mediaUpload.current}/${st.mediaUpload.total}:${st.mediaUpload.name}` : null,
       // Continuity pin renders on gallery cards (📌 button state + thumb badge).
       pin: st.project?.continuity_settings?.identity_pin_ref,
       // Reference marks render the same way (R button + numbered badge), and their ORDER