build: add Windows portable EXE packaging scripts

- scripts/build-icon.js — generates icon.png/ico/tray-icon.png
  from pure Node.js (no dependencies, zlib + PNG/ICO encoder)
- scripts/fix-wincodeSign.js — pre-populates electron-builder
  winCodeSign cache by extracting the .7z while ignoring macOS
  symlinks (which fail on Windows without SeCreateSymbolicLink)
- package.json: add fix-wincodeSign script, cross-env, electron-builder
  downgraded to v24 (stable portable target), CSC signing disabled

Build: npm run build:win → dist-electron/SRT-Streamer-Portable-1.0.0.exe

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

scripts/build-icon.js

@@ -0,0 +1,153 @@
+/**
+ * Generates assets/icon.png and assets/icon.ico
+ * using only built-in Node.js (no external deps).
+ *
+ * ICO contains an embedded 256x256 PNG (Vista+ format).
+ */
+'use strict'
+const zlib = require('zlib')
+const fs   = require('fs')
+const path = require('path')
+
+// ─── CRC32 for PNG chunks ─────────────────────────────────────────────────────
+function crc32(buf) {
+  let crc = 0xFFFFFFFF
+  for (let i = 0; i < buf.length; i++) {
+    crc ^= buf[i]
+    for (let j = 0; j < 8; j++) crc = (crc & 1) ? (0xEDB88320 ^ (crc >>> 1)) : (crc >>> 1)
+  }
+  return (crc ^ 0xFFFFFFFF) >>> 0
+}
+function pngChunk(type, data) {
+  const t = Buffer.from(type, 'ascii')
+  const len = Buffer.alloc(4); len.writeUInt32BE(data.length)
+  const crcVal = Buffer.alloc(4); crcVal.writeUInt32BE(crc32(Buffer.concat([t, data])))
+  return Buffer.concat([len, t, data, crcVal])
+}
+
+// ─── Minimal PNG encoder (RGBA, no interlace) ─────────────────────────────────
+function makePNG(size, drawFn) {
+  const stride = 1 + size * 4           // filter byte + RGBA per pixel
+  const raw    = Buffer.alloc(size * stride)
+
+  for (let y = 0; y < size; y++) {
+    raw[y * stride] = 0                 // filter: None
+    for (let x = 0; x < size; x++) {
+      const [r, g, b, a = 255] = drawFn(x, y, size)
+      const off = y * stride + 1 + x * 4
+      raw[off] = r; raw[off+1] = g; raw[off+2] = b; raw[off+3] = a
+    }
+  }
+
+  const ihdrData = Buffer.alloc(13)
+  ihdrData.writeUInt32BE(size, 0)
+  ihdrData.writeUInt32BE(size, 4)
+  ihdrData[8]  = 8   // bit depth
+  ihdrData[9]  = 6   // RGBA
+  ihdrData[10] = 0; ihdrData[11] = 0; ihdrData[12] = 0
+
+  return Buffer.concat([
+    Buffer.from([0x89,0x50,0x4e,0x47,0x0d,0x0a,0x1a,0x0a]), // PNG sig
+    pngChunk('IHDR', ihdrData),
+    pngChunk('IDAT', zlib.deflateSync(raw, { level: 9 })),
+    pngChunk('IEND', Buffer.alloc(0))
+  ])
+}
+
+// ─── Draw function ────────────────────────────────────────────────────────────
+function drawIcon(x, y, S) {
+  const cx = S / 2, cy = S / 2
+  const r  = S * 0.48          // outer radius
+
+  // Distance from center
+  const dx = x - cx, dy = y - cy
+  const dist = Math.sqrt(dx*dx + dy*dy)
+
+  // Outside circle → transparent
+  if (dist > r) return [0, 0, 0, 0]
+
+  // Background gradient: dark blue
+  const t  = dist / r
+  const bg = [
+    Math.round(26  + t * 8),
+    Math.round(26  + t * 6),
+    Math.round(46  + t * 10),
+    255
+  ]
+
+  // ── Play triangle ──────────────────────────────────────────────────────────
+  const tLeft  = cx - S * 0.22
+  const tRight = cx + S * 0.28
+  const tTop   = cy - S * 0.30
+  const tBot   = cy + S * 0.30
+  // Point is inside triangle if:  (x >= tLeft) AND left of right edge
+  const edgeTop = tLeft + (tRight - tLeft) * (y - tTop) / (tBot - tTop)
+  const edgeBot = tLeft + (tRight - tLeft) * (tBot - y) / (tBot - tTop)
+  const inTri = x >= tLeft && x <= edgeTop && x <= edgeBot
+              && y >= tTop  && y <= tBot
+
+  if (inTri) {
+    // Accent blue gradient
+    const fx = (x - tLeft) / (tRight - tLeft)
+    return [
+      Math.round(79  + fx * 50),
+      Math.round(142 + fx * 30),
+      Math.round(247 - fx * 50),
+      255
+    ]
+  }
+
+  // ── Red "LIVE" dot (top-right) ─────────────────────────────────────────────
+  const dotX = cx + S * 0.25, dotY = cy - S * 0.26, dotR = S * 0.12
+  const ddx = x - dotX, ddy = y - dotY
+  const dotDist = Math.sqrt(ddx*ddx + ddy*ddy)
+  if (dotDist <= dotR) {
+    const inner = dotR * 0.45
+    if (dotDist <= inner) return [255, 255, 255, 255]  // white center
+    return [239, 68, 68, 255]                           // red ring
+  }
+
+  return bg
+}
+
+// ─── Wrap PNG in ICO ──────────────────────────────────────────────────────────
+function pngToIco(pngBuf, size) {
+  const header = Buffer.alloc(6)
+  header.writeUInt16LE(0, 0)            // reserved
+  header.writeUInt16LE(1, 2)            // type: icon
+  header.writeUInt16LE(1, 4)            // image count
+
+  const entry = Buffer.alloc(16)
+  entry[0] = size >= 256 ? 0 : size     // width  (0 = 256)
+  entry[1] = size >= 256 ? 0 : size     // height (0 = 256)
+  entry[2] = 0                          // color count
+  entry[3] = 0                          // reserved
+  entry.writeUInt16LE(1, 4)             // planes
+  entry.writeUInt16LE(32, 6)            // bit count
+  entry.writeUInt32LE(pngBuf.length, 8) // bytes in image
+  entry.writeUInt32LE(6 + 16, 12)       // offset = header + 1 entry
+
+  return Buffer.concat([header, entry, pngBuf])
+}
+
+// ─── Main ─────────────────────────────────────────────────────────────────────
+const assetsDir = path.join(__dirname, '..', 'assets')
+if (!fs.existsSync(assetsDir)) fs.mkdirSync(assetsDir, { recursive: true })
+
+console.log('Generating icon 256×256 PNG…')
+const png256 = makePNG(256, drawIcon)
+fs.writeFileSync(path.join(assetsDir, 'icon.png'), png256)
+console.log('  ✓ assets/icon.png')
+
+console.log('Wrapping in ICO…')
+const ico = pngToIco(png256, 256)
+fs.writeFileSync(path.join(assetsDir, 'icon.ico'), ico)
+console.log('  ✓ assets/icon.ico')
+
+// 16px tray icon
+console.log('Generating tray icon 16×16…')
+const png16 = makePNG(16, drawIcon)
+fs.writeFileSync(path.join(assetsDir, 'tray-icon.png'), png16)
+console.log('  ✓ assets/tray-icon.png')
+
+console.log('Done.')