V1.0: Class 1 fax — real-world 4-page send to external number confirmed

Core features:
- Class 1 T.30 protocol: full send/receive implementation
- HDLC: DLE-stuffing, FCS strip, USR5637 bit-reversal handling
- T.4 MH encoder/decoder (1728px A4 standard)
- Document pipeline: PDF (Ghostscript), PNG, TIFF input
- Width clamping: US Letter 1734px → 1728px fax standard
- Cover page: CJK rasterization (TW/CN/JP/EN), TIFF + HTML output
- OCR verification: Tesseract 5 with eng+chi_tra, CJK space-tolerant
- API server (axum): health, send, jobs, cover, retry, cancel
- Background worker: auto-poll queue, speed fallback, retry policy
- Modem detection, pool management

Real-world test results (2026-07-23):
- V90 → 25153038: 4 pages, V.17 12000 bps, 2:33 ✅
- USR5637 → 25153038: 4 pages, V.17 12000 bps, 2:26 ✅
- Both faxes confirmed received on remote machine

Tested: loopback (100% pixel match), multi-page, all input formats,
cover pages, OCR verify, API endpoints, worker processing.
13 unit tests pass, 0 new clippy warnings.

scripts/create_test_image.py

@@ -0,0 +1,76 @@
+#!/usr/bin/env python3
+
+from PIL import Image, ImageDraw, ImageFont
+import sys
+
+def create_test_image(text, output_path, language='english'):
+    W, H = 1728, 2291
+    img = Image.new('L', (W, H), 255)
+    draw = ImageDraw.Draw(img)
+    
+    font_path = '/System/Library/Fonts/Helvetica.ttc'
+    try:
+        font = ImageFont.truetype(font_path, 44)
+    except:
+        font = ImageFont.load_default()
+    
+    lines = text.split('\n')
+    y = 100
+    for line in lines:
+        draw.text((100, y), line, fill=0, font=font)
+        y += 60
+    
+    img.save(output_path, dpi=(204, 196))
+    print(f"Test image created: {output_path}")
+
+if __name__ == '__main__':
+    if len(sys.argv) < 3:
+        print("Usage: python create_test_image.py <output_path> <language>")
+        sys.exit(1)
+    
+    output_path = sys.argv[1]
+    language = sys.argv[2]
+    
+    test_texts = {
+        'english': """FAX COVER PAGE
+
+TO: John Smith
+FROM: Jane Doe
+DATE: 2024-01-15
+SUBJECT: Meeting Notes
+PAGES: 5
+
+Dear Mr. Smith,
+
+Please review the attached meeting notes before our discussion tomorrow.
+
+Best regards,
+Jane Doe""",
+        'chinese': """傳真封面頁
+
+收件人：張三
+發件人：李四
+日期：2024-01-15
+主題：業務合作提案
+頁數：5
+
+請參閱附件內容，謝謝。
+
+李四""",
+        'mixed': """FAX COVER PAGE
+
+TO: John Smith (張三)
+FROM: Jane Doe (李四)
+DATE: 2024-01-15
+SUBJECT: Business Proposal (業務提案)
+PAGES: 5
+
+This fax contains business documents.
+請參閱附件內容。
+
+Best regards,
+Jane Doe""",
+    }
+    
+    text = test_texts.get(language, test_texts['english'])
+    create_test_image(text, output_path, language)