fix(receiver): revert indicator to framesWithQR/accepted/needed with correct math

- framesWithQR now counts ALL frames with a valid QR (including duplicates),
  not just deduplicated ones. Moved increment before dedup check.
- acceptedPackets already correctly counts linearly-independent packets
  (rank increase), capped at K per generation by the decoder.
- neededPackets = K * sourceGenerations, computed from constants.
- Keep generation count (solvedGens/sourceGens) as secondary indicator.

This gives an honest rough progress bar: useful can approach or briefly
touch required while some generations are still partially filled, but the
generation count is the definitive completion signal.

src/app/routes/receiver.tsx

@@ -155,6 +155,7 @@ export function ReceiverPage() {
   const [totalFrames, setTotalFrames] = useState(0);
   const [framesWithQR, setFramesWithQR] = useState(0);
   const [acceptedPackets, setAcceptedPackets] = useState(0);
+  const [neededPackets, setNeededPackets] = useState(0);
   const [receivedFile, setReceivedFile] = useState<ReceivedFile | null>(null);
   const [receivedText, setReceivedText] = useState('');
   const [error, setError] = useState('');
@@ -181,6 +182,7 @@ export function ReceiverPage() {
           setTotalFrames(msg.totalFrames ?? 0);
           setFramesWithQR(msg.framesWithQR ?? 0);
           setAcceptedPackets(msg.acceptedPackets ?? 0);
+          setNeededPackets(msg.neededPackets ?? 0);
           setSolvedGens(msg.solvedGenerations ?? 0);
           setSourceGens(msg.sourceGenerations ?? 0);
           if (msg.dataLength) {
@@ -281,6 +283,7 @@ export function ReceiverPage() {
     setTotalFrames(0);
     setFramesWithQR(0);
     setAcceptedPackets(0);
+    setNeededPackets(0);
     setElapsedMs(0);
     setThroughputKbps(0);
     setSolvedGens(0);
@@ -354,6 +357,7 @@ export function ReceiverPage() {
     setTotalFrames(0);
     setFramesWithQR(0);
     setAcceptedPackets(0);
+    setNeededPackets(0);
     setElapsedMs(0);
     setThroughputKbps(0);
     setSolvedGens(0);
@@ -548,13 +552,13 @@ export function ReceiverPage() {
           {scanning && (
             <div style={S.statsBar}>
               <span>
+                QRs{' '}
                 <span style={S.statValue}>
-                  {framesWithQR}/{solvedGens}/{sourceGens}
-                </span>{' '}
-                gens
+                  {framesWithQR}/{acceptedPackets}/{neededPackets || '?'}
+                </span>
               </span>
               <span>
-                pkts <span style={S.statValue}>{acceptedPackets}</span>
+                gens <span style={S.statValue}>{solvedGens}/{sourceGens}</span>
               </span>
               <span>
                 time <span style={S.statValue}>{formatDuration(elapsedMs)}</span>
@@ -615,13 +619,13 @@ export function ReceiverPage() {
           {scanning && (
             <div style={S.statsBar}>
               <span>
+                QRs{' '}
                 <span style={S.statValue}>
-                  {framesWithQR}/{solvedGens}/{sourceGens}
-                </span>{' '}
-                gens
+                  {framesWithQR}/{acceptedPackets}/{neededPackets || '?'}
+                </span>
               </span>
               <span>
-                pkts <span style={S.statValue}>{acceptedPackets}</span>
+                gens <span style={S.statValue}>{solvedGens}/{sourceGens}</span>
               </span>
               <span>
                 time <span style={S.statValue}>{formatDuration(elapsedMs)}</span>

src/workers/decode.worker.ts

@@ -112,12 +112,12 @@ function handleFrame(imageData: ImageData): void {
   current.isCompressed = h.compressed;
 
   current.stats.totalFrames++;
+  current.stats.framesWithQR++;
 
   // Dedup: generationIndex:symbolIndex
   const dedupKey = `${h.generationIndex}:${h.symbolIndex}`;
   if (current.dedup.has(dedupKey)) return;
   current.dedup.add(dedupKey);
-  current.stats.framesWithQR++;
 
   // Feed to decoder
   const gen = h.generationIndex;
@@ -251,12 +251,14 @@ function reconstructData(state: DecodeState): void {
 function reportProgress(state: DecodeState): void {
   const totalGens = state.totalGenerations;
   const solvedGens = state.solvedGenerations.size;
+  const needed = state.sourceGenerations > 0 ? K * state.sourceGenerations : 0;
 
-    self.postMessage({
+  self.postMessage({
     type: 'progress',
     totalFrames: state.stats.totalFrames,
     framesWithQR: state.stats.framesWithQR,
     acceptedPackets: state.stats.acceptedPackets,
+    neededPackets: needed,
     receivedPackets: state.receivedPackets,
     solvedGenerations: solvedGens,
     totalGenerations: totalGens,