fix(media): Increase max dimension to 12000px for modern phone cameras

Modern iPhones (48MP) and other phones produce images larger than 4096px.
Since optimize_image() resizes them anyway, the input limit was too
restrictive. Increased from 4096x4096 to 12000x12000.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

starpunk/media.py

@@ -38,7 +38,7 @@ ALLOWED_MIME_TYPES = {
 # Limits per Q&A and ADR-058 (updated in v1.4.0)
 MAX_FILE_SIZE = 50 * 1024 * 1024  # 50MB (v1.4.0)
 MAX_OUTPUT_SIZE = 10 * 1024 * 1024  # 10MB target after optimization (v1.4.0)
-MAX_DIMENSION = 4096              # 4096x4096 max
+MAX_DIMENSION = 12000             # 12000x12000 max input (v1.4.2 - supports modern phone cameras)
 RESIZE_DIMENSION = 2048           # Auto-resize to 2048px (default)
 MIN_QUALITY = 70                  # Minimum JPEG quality before rejection (v1.4.0)
 MIN_DIMENSION = 640               # Minimum dimension before rejection (v1.4.0)
@@ -194,7 +194,8 @@ def validate_image(file_data: bytes, filename: str) -> Tuple[bytes, str, int, in
     else:
         raise ValueError("Could not determine image format")
 
-    # Check dimensions
+    # Check dimensions (v1.4.2: increased to 12000px to support modern phone cameras)
+    # Images will be resized by optimize_image() anyway
     width, height = img.size
     if max(width, height) > MAX_DIMENSION:
         raise ValueError(f"Image dimensions too large. Maximum is {MAX_DIMENSION}x{MAX_DIMENSION} pixels")