[WIP] Ensure HEIC and AVIF have consistent metadata extraction (#63)

* Initial plan

* Enhanced HEIC and AVIF metadata extraction to match other formats

Added comprehensive EXIF parsing including:
- IFD0 tags: description, author, copyright
- Exif Sub-IFD tags: flash, whiteBalance, lensMake, lensModel, userComment
- GPS IFD: full latitude/longitude parsing
- Updated field count from 11 to 19 fields in both formats
- Updated README and documentation to reflect enhanced support

Co-authored-by: Hexagon <419737+Hexagon@users.noreply.github.com>

* Add safety bounds checks to EXIF parsing loops

- Added upper bounds (100 entries max) to parseExifSubIFD loops in HEIC and AVIF
- Added upper bounds (100 entries max) to parseGPSIFD loops in HEIC and AVIF
- Prevents excessive iterations with malformed EXIF data

Co-authored-by: Hexagon <419737+Hexagon@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: Hexagon <419737+Hexagon@users.noreply.github.com>

Author: Copilot

README.md

@@ -255,8 +255,8 @@ Image.getSupportedMetadata("jpeg"); // Full camera metadata + GPS (21 fields)
 Image.getSupportedMetadata("tiff"); // Comprehensive EXIF + GPS + InteropIFD (23+ fields)
 Image.getSupportedMetadata("png"); // DateTime, GPS, DPI, basic text (9 fields)
 Image.getSupportedMetadata("webp"); // Enhanced XMP + GPS (15 fields - includes camera metadata!)
-Image.getSupportedMetadata("heic"); // Camera metadata + GPS (11 fields)
-Image.getSupportedMetadata("avif"); // Camera metadata + GPS (11 fields)
+Image.getSupportedMetadata("heic"); // Full camera metadata + GPS (19 fields)
+Image.getSupportedMetadata("avif"); // Full camera metadata + GPS (19 fields)
 ```
 
 **Format Highlights:**
@@ -267,8 +267,10 @@ Image.getSupportedMetadata("avif"); // Camera metadata + GPS (11 fields)
 - **WebP**: Enhanced XMP implementation with Dublin Core, EXIF, and TIFF
   namespaces
 - **PNG**: Basic EXIF support via eXIf chunk plus GPS coordinates
-- **HEIC**: Camera metadata and GPS extraction (runtime-dependent encoding)
-- **AVIF**: Camera metadata and GPS extraction (runtime-dependent encoding)
+- **HEIC**: Full EXIF metadata extraction including camera settings, GPS, and
+  image info (runtime-dependent encoding)
+- **AVIF**: Full EXIF metadata extraction including camera settings, GPS, and
+  image info (runtime-dependent encoding)
 
 ## Documentation
 

docs/src/metadata.md

@@ -156,23 +156,23 @@ const pngFields = Image.getSupportedMetadata("png");
 
 // Check HEIC support
 const heicFields = Image.getSupportedMetadata("heic");
-// HEIC supports camera metadata and GPS (11 fields)
+// HEIC supports full camera metadata and GPS (19 fields)
 
 // Check AVIF support
 const avifFields = Image.getSupportedMetadata("avif");
-// AVIF supports camera metadata and GPS (11 fields)
+// AVIF supports full camera metadata and GPS (19 fields)
 ```
 
 ### Format Comparison
 
-| Format   | Fields | Implementation                            |
-| -------- | ------ | ----------------------------------------- |
-| **JPEG** | 21     | Full EXIF (IFD0 + Exif Sub-IFD + GPS IFD) |
-| **TIFF** | 23+    | Complete EXIF 3.0 support with InteropIFD |
-| **WebP** | 15     | EXIF DateTime/GPS + Enhanced XMP          |
-| **PNG**  | 9      | eXIf chunk + pHYs + tEXt chunks           |
-| **HEIC** | 11     | EXIF metadata extraction (runtime-based)  |
-| **AVIF** | 11     | EXIF metadata extraction (runtime-based)  |
+| Format   | Fields | Implementation                                            |
+| -------- | ------ | --------------------------------------------------------- |
+| **JPEG** | 21     | Full EXIF (IFD0 + Exif Sub-IFD + GPS IFD)                 |
+| **TIFF** | 23+    | Complete EXIF 3.0 support with InteropIFD                 |
+| **HEIC** | 19     | Full EXIF metadata extraction (IFD0 + Exif Sub-IFD + GPS) |
+| **AVIF** | 19     | Full EXIF metadata extraction (IFD0 + Exif Sub-IFD + GPS) |
+| **WebP** | 15     | EXIF DateTime/GPS + Enhanced XMP                          |
+| **PNG**  | 9      | eXIf chunk + pHYs + tEXt chunks                           |
 
 ## EXIF 3.0 Specification Compliance