Smart download filenames: 'Artist - Title - REEL.mp4' + validation

Two improvements:

1. DOWNLOAD FILENAME: instead of 'reel_<job-id>.mp4' (e.g. reel_25e076af7600.mp4),
   downloads now have descriptive names like:
   - 'Lady Gaga - Abracadabra - REEL.mp4'
   - 'Modrijani - S teboj - REEL.mp4'
   - 'Sarah Connor - FICKA - REEL.mp4'

2. PRE-UPLOAD VALIDATION: when filename doesn't follow 'Artist - Title' format,
   browser prompts user for both fields. Without them, upload is blocked.
   This prevents files with names like '12345.mp4' or 'video_final.mp4' from
   being processed without identifying info.

Implementation:
- parse_artist_title() helper handles common formats:
  - 'Artist - Title.mp4' / 'Artist – Title' (em-dash)
  - 'Artist | Title' / 'Artist : Title'
  - Strips noise: '(Official Music Video)', '(Audio)', '(HD)', '[Lyric Video]'
- Client-side parser mirrors backend (validation before upload)
- Backend accepts artist + title form fields (override parsed)
- Job stored with parsed_artist + parsed_title + has_clean_name fields
- YouTube jobs auto-fetch title via yt-dlp --info-only and parse it
- Filename hint to Scribe/Claude uses parsed values (cleaner than raw filename)
- Download endpoint uses build_download_filename() for content-disposition
- Jobs list shows 'Artist — Title' instead of raw filename

Result: downloaded reels are auto-named correctly for Facebook/Instagram
upload, no more renaming files manually.

templates/index.html

@@ -443,11 +443,13 @@
     const dz = $("#dropzone");
     const fileInput = $("#file-input");
     let pendingFile = null;
+    let pendingArtist = null;
+    let pendingTitle = null;
+    
     dz.addEventListener("click", () => fileInput.click());
     fileInput.addEventListener("change", () => {
       if (fileInput.files[0]) {
-        pendingFile = fileInput.files[0];
-        dz.querySelector("div").textContent = `📹 ${pendingFile.name}`;
+        handleFileSelected(fileInput.files[0]);
       }
     });
     ["dragover", "dragenter"].forEach(ev =>
@@ -456,11 +458,82 @@
       dz.addEventListener(ev, e => { e.preventDefault(); dz.classList.remove("drag"); }));
     dz.addEventListener("drop", e => {
       const f = e.dataTransfer.files[0];
-      if (f) {
-        pendingFile = f;
-        dz.querySelector("div").textContent = `📹 ${f.name}`;
-      }
+      if (f) handleFileSelected(f);
     });
+    
+    // Klient-side parser (mora ustrezati backend parse_artist_title)
+    function parseArtistTitle(filename) {
+      if (!filename) return [null, null];
+      let name = filename.replace(/\.[^.]+$/, "");  // remove ext
+      
+      // Odstrani noise
+      const noise = [
+        /\(Official\s+(?:Music\s+)?Video\)/gi,
+        /\(Officia[lk]\s+Audio\)/gi,
+        /\(Offizielles\s+(?:Musik)?[Vv]ideo\)/gi,
+        /\(Lyric[s]?\s+Video\)/gi,
+        /\(Audio\)/gi,
+        /\(HD\)|\(HQ\)|\(4K\)/gi,
+        /\(Live\)|\(Remix\)|\(Remaster(?:ed)?\s*\d{0,4}\)/gi,
+        /\[Official.*?\]|\[Music.*?\]|\[Audio.*?\]/gi,
+        /\bofficial\s+video\b|\bofficial\s+audio\b/gi,
+        /\boriginal\s+(?:video|audio)\b/gi,
+        /\bMV\b|\b4K\b|\bHD\b|\bHQ\b/g,
+      ];
+      for (const r of noise) name = name.replace(r, "");
+      name = name.replace(/\s+/g, " ").trim();
+      
+      // Probaj separatorje
+      for (const sep of [" - ", " – ", " — ", " | ", " : "]) {
+        if (name.includes(sep)) {
+          const parts = name.split(sep);
+          if (parts.length >= 2) {
+            const artist = parts[0].trim().replace(/^[\s\-–—|.:_]+|[\s\-–—|.:_]+$/g, "");
+            const title = parts.slice(1).join(sep).trim().replace(/^[\s\-–—|.:_]+|[\s\-–—|.:_]+$/g, "");
+            if (artist && title) return [artist, title];
+          }
+        }
+      }
+      return [null, null];
+    }
+    
+    function handleFileSelected(f) {
+      const [artist, title] = parseArtistTitle(f.name);
+      
+      if (!artist || !title) {
+        // Ni razvidno ime — vprašaj uporabnika
+        const userArtist = prompt(
+          `❗ Iz imena datoteke ni razviden izvajalec in naslov.\n\n` +
+          `Datoteka: "${f.name}"\n\n` +
+          `Vpiši IZVAJALCA (npr. "Lady Gaga"):`,
+          ""
+        );
+        if (!userArtist || !userArtist.trim()) {
+          alert("⛔ Brez izvajalca ne morem nadaljevati.\n\nPoimenuj datoteko v formatu:\n  Izvajalec - Naslov.mp4");
+          fileInput.value = "";
+          return;
+        }
+        const userTitle = prompt(
+          `Vpiši NASLOV pesmi (npr. "Abracadabra"):`,
+          ""
+        );
+        if (!userTitle || !userTitle.trim()) {
+          alert("⛔ Brez naslova ne morem nadaljevati.");
+          fileInput.value = "";
+          return;
+        }
+        pendingArtist = userArtist.trim();
+        pendingTitle = userTitle.trim();
+      } else {
+        pendingArtist = artist;
+        pendingTitle = title;
+      }
+      
+      pendingFile = f;
+      dz.querySelector("div").innerHTML = 
+        `📹 <b>${pendingArtist} — ${pendingTitle}</b>` +
+        `<div style="font-size: 11px; color: var(--muted); margin-top: 4px;">${f.name} (${(f.size/1024/1024).toFixed(1)} MB)</div>`;
+    }
 
     // ─── Settings collector ─────────────────────────
     function collectSettings() {
@@ -610,6 +683,8 @@
           }
           const fd = new FormData();
           fd.append("file", pendingFile);
+          if (pendingArtist) fd.append("artist", pendingArtist);
+          if (pendingTitle) fd.append("title", pendingTitle);
 
           showLive("Nalaganje datoteke", `${pendingFile.name} (${(pendingFile.size / 1024 / 1024).toFixed(1)} MB)`, 0);
 
@@ -755,7 +830,9 @@
 
       const title = job.source_type === "youtube"
         ? (job.youtube_url || "YouTube")
-        : (job.filename || job.id);
+        : (job.parsed_artist && job.parsed_title 
+            ? `${job.parsed_artist} — ${job.parsed_title}` 
+            : (job.filename || job.id));
 
       const sizeStr = job.output_size_mb ? `${job.output_size_mb} MB` :
                       job.size_mb ? `${job.size_mb} MB` : "";