Add Enigma2/OpenWebif M3U support: program mapping and zap-before-streaming

- Parse #EXTVLCOPT:program=N from M3U playlists (both full and streaming
  parsers, per channel, strict mode) and store it on playlist items
- Transcode multi-program MPEG-TS streams by mapping only the selected
  program's first video and audio stream (DVB teletext/subtitles in the
  program otherwise make FFmpeg fail to produce HLS)
- Optional per-source "zap before streaming" with configurable delay:
  POST /api/openwebif/zap takes sourceId + streamId, requires an enabled,
  zap-enabled M3U source containing that channel, derives the receiver
  from the configured source URL (never from the client), validates the
  Enigma2 service reference, uses a timeout without redirects and does
  not echo the receiver response
- Live TV: Stop button, and stop playback when leaving the page
- Tests for ordinary and program-tagged playlists and the zap endpoint

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

server/services/m3uParser.js

@@ -1,3 +1,5 @@
+'use strict';
+
 /**
  * M3U Playlist Parser (Streaming)
  * Parses EXTM3U format playlists and extracts channel information line-by-line
@@ -88,6 +90,7 @@ async function parse(input) {
     const groupsSet = new Set();
     let currentInfo = null;
     let currentGroup = null;
+    let currentVlcProgram = null;
 
     let lines;
 
@@ -121,6 +124,11 @@ async function parse(input) {
             if (currentInfo) {
                 currentInfo.groupTitle = currentGroup;
             }
+        } else if (trimmed.startsWith('#EXTVLCOPT:program=')) {
+            currentVlcProgram = trimmed.split('=')[1]?.trim() || null;
+            if (currentInfo) {
+                currentInfo.program = currentVlcProgram;
+            }
         } else if (!trimmed.startsWith('#')) {
             // This is a stream URL
             if (currentInfo) {
@@ -132,9 +140,11 @@ async function parse(input) {
                     ...currentInfo,
                     id: stableId,
                     url: trimmed,
+                    program: currentVlcProgram,
                     groupTitle: groupTitle
                 });
                 currentInfo = null;
+                currentVlcProgram = null;
             }
         }
     }
@@ -187,6 +197,7 @@ async function* parseStreaming(input, batchSize = 500) {
     const groupsSet = new Set();
     let currentInfo = null;
     let currentGroup = null;
+    let currentVlcProgram = null;
     let batch = [];
 
     let lines;
@@ -216,6 +227,11 @@ async function* parseStreaming(input, batchSize = 500) {
             if (currentInfo) {
                 currentInfo.groupTitle = currentGroup;
             }
+        } else if (trimmed.startsWith('#EXTVLCOPT:program=')) {
+            currentVlcProgram = trimmed.split('=')[1]?.trim() || null;
+            if (currentInfo) {
+                currentInfo.program = currentVlcProgram;
+            }
         } else if (!trimmed.startsWith('#')) {
             if (currentInfo) {
                 const groupTitle = currentInfo.groupTitle || currentGroup || 'Uncategorized';
@@ -225,9 +241,11 @@ async function* parseStreaming(input, batchSize = 500) {
                     ...currentInfo,
                     id: stableId,
                     url: trimmed,
+                    program: currentVlcProgram,
                     groupTitle: groupTitle
                 });
                 currentInfo = null;
+                currentVlcProgram = null;
 
                 // Yield batch when full
                 if (batch.length >= batchSize) {