fix(i18n): keep English pixel-identical and stored data English

From the English-parity and breakage review against main:
- English wording back to main: "Configured Source", the "SHARED SUBJECT"
  fallback, CCTV calibration "RANGE 120m".
- Voice header and CCTV calibration chip/select tweaks for long labels now
  apply to non-English only (html:not([lang='en'])); English matches main.
  The scene select font change is scoped the same way.
- New scenes and shots store their default title in English ("Scene 3",
  "Shot 2") and translate it when shown, so a title captured in one language
  does not leak into projects, storage or shared JSON.
- Choosing a language with storage blocked keeps it in ?lang instead of
  silently doing nothing.
- One picked import file shows its name again.
- qa-l9-matrix reads the voice state from data-status, not the label.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/ui/sceneSharing.js

@@ -126,9 +126,13 @@ export function createSceneDialog(title, onClose) {
     const chosen = document.createElement('span');
     const showChosen = () => {
       const count = node.files?.length || 0;
-      chosen.textContent = count
-        ? tn(count, '{count} file selected', '{count} files selected')
-        : t('No file chosen');
+      // One file shows its name, like the browser's own picker did.
+      chosen.textContent =
+        count === 1
+          ? node.files[0].name
+          : count
+            ? tn(count, '{count} file selected', '{count} files selected')
+            : t('No file chosen');
     };
     showChosen();
     row.append(chooser, chosen);