examples: add example plugins

Signed-off-by: NotAShelf <raf@notashelf.dev>
Change-Id: I9eac30c7d4c1c89178f4930b215e523d6a6a6964

examples/plugins/heif-support/README.md

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+# HEIF/HEIC Support Plugin
+
+This example plugin adds support for HEIF (High Efficiency Image Format) and HEIC (HEIF Container) to Pinakes.
+
+## Overview
+
+HEIF is a modern image format that provides better compression than JPEG while maintaining higher quality. This plugin enables Pinakes to:
+- Recognize HEIF/HEIC files as a media type
+- Extract metadata from HEIF images
+- Generate thumbnails from HEIF images
+
+## Features
+
+- **Media Type Registration**: Registers `.heif`, `.heic`, `.hif` extensions as image media types
+- **EXIF Extraction**: Extracts EXIF metadata including camera info, GPS coordinates, timestamps
+- **Thumbnail Generation**: Generates thumbnails in JPEG, PNG, or WebP format
+- **Resource Limits**: Configurable memory and CPU limits for safe processing
+- **Large Image Support**: Handles images up to 8192x8192 pixels
+
+## Supported Formats
+
+- **HEIF**: High Efficiency Image Format (`.heif`, `.hif`)
+- **HEIC**: HEIF Container format used by Apple devices (`.heic`)
+- **HEIF Sequences**: Multi-image HEIF files
+- **HEIF with Alpha**: HEIF images with transparency
+
+## Implementation
+
+The plugin implements three traits:
+
+### MediaTypeProvider
+
+```rust
+#[async_trait]
+impl MediaTypeProvider for HeifPlugin {
+    fn supported_media_types(&self) -> Vec<MediaTypeDefinition> {
+        vec![MediaTypeDefinition {
+            id: "heif".to_string(),
+            name: "HEIF Image".to_string(),
+            category: "image".to_string(),
+            extensions: vec!["heif".to_string(), "heic".to_string(), "hif".to_string()],
+            mime_types: vec!["image/heif".to_string(), "image/heic".to_string()],
+            icon: Some("image".to_string()),
+        }]
+    }
+
+    async fn can_handle(&self, path: &PathBuf, mime_type: Option<&str>) -> PluginResult<bool> {
+        // Check file extension and/or MIME type
+    }
+}
+```
+
+### MetadataExtractor
+
+```rust
+#[async_trait]
+impl MetadataExtractor for HeifPlugin {
+    async fn extract_metadata(&self, path: &PathBuf) -> PluginResult<ExtractedMetadata> {
+        // 1. Parse HEIF file structure
+        // 2. Extract EXIF metadata
+        // 3. Get image dimensions
+        // 4. Return ExtractedMetadata
+    }
+
+    fn supported_types(&self) -> Vec<String> {
+        vec!["heif".to_string()]
+    }
+}
+```
+
+### ThumbnailGenerator
+
+```rust
+#[async_trait]
+impl ThumbnailGenerator for HeifPlugin {
+    async fn generate_thumbnail(
+        &self,
+        path: &PathBuf,
+        output_path: &PathBuf,
+        options: ThumbnailOptions,
+    ) -> PluginResult<ThumbnailInfo> {
+        // 1. Decode HEIF image
+        // 2. Resize to thumbnail dimensions
+        // 3. Encode to output format
+        // 4. Save to output_path
+        // 5. Return ThumbnailInfo
+    }
+
+    fn supported_types(&self) -> Vec<String> {
+        vec!["heif".to_string()]
+    }
+}
+```
+
+## Dependencies
+
+The plugin uses the following Rust crates (compiled to WASM):
+- `libheif-rs`: HEIF decoding and encoding
+- `image`: Image processing and thumbnail generation
+- `kamadak-exif`: EXIF metadata parsing
+
+## Building
+
+### Prerequisites
+
+```bash
+# Install WASM target
+rustup target add wasm32-wasi
+
+# Install wasm-tools for optimization (provides strip functionality)
+cargo install wasm-tools
+```
+
+### Build Process
+
+```bash
+# Build the plugin
+cargo build --target wasm32-wasi --release
+
+# Strip debug symbols to reduce size
+wasm-tools strip target/wasm32-wasi/release/heif_support.wasm -o target/wasm32-wasi/release/heif_support.wasm
+
+# Copy to plugin directory
+cp target/wasm32-wasi/release/heif_support.wasm .
+```
+
+### Size Optimization
+
+```bash
+# Use wasm-opt for further optimization
+wasm-opt -Oz heif_support.wasm -o heif_support_optimized.wasm
+```
+
+## Installation
+
+### Manual Installation
+
+```bash
+# Copy plugin directory to Pinakes plugins directory
+cp -r examples/plugins/heif-support ~/.config/pinakes/plugins/
+```
+
+### Via API
+
+```bash
+curl -X POST http://localhost:3000/api/v1/plugins/install \
+  -H "Content-Type: application/json" \
+  -d '{"source": "/path/to/heif-support"}'
+```
+
+### Via Plugin Manager
+
+```bash
+pinakes plugin install /path/to/heif-support
+```
+
+## Configuration
+
+The plugin can be configured through the `config` section in `plugin.toml`:
+
+### EXIF Extraction
+- `extract_exif`: Enable EXIF metadata extraction (default: true)
+
+### Thumbnail Generation
+- `generate_thumbnails`: Enable thumbnail generation (default: true)
+- `thumbnail_quality`: JPEG quality for thumbnails, 1-100 (default: 85)
+- `thumbnail_format`: Output format - "jpeg", "png", or "webp" (default: "jpeg")
+
+### Resource Limits
+- `max_memory_mb`: Maximum memory the plugin can use in megabytes (default: 256, set in `[capabilities]`)
+- `max_width`: Maximum image width to process (default: 8192)
+- `max_height`: Maximum image height to process (default: 8192)
+
+## Security
+
+### Capabilities
+
+- **Filesystem Read**: Only files being processed (via Pinakes)
+- **Filesystem Write**: Thumbnail directory only
+- **Network**: Disabled
+- **Environment**: No access
+
+### Resource Limits
+
+- **Memory**: 256 MB maximum
+- **CPU Time**: 30 seconds maximum per operation
+
+### Sandboxing
+
+The plugin runs in a WASM sandbox with:
+- No access to host filesystem beyond granted paths
+- No network access
+- No arbitrary code execution
+- Memory and CPU time limits enforced by runtime
+
+## Performance
+
+### Typical Performance
+
+- **Metadata Extraction**: ~50-100ms for typical HEIF files
+- **Thumbnail Generation**: ~200-500ms depending on source image size
+- **Memory Usage**: 50-150 MB typical, 256 MB maximum
+
+### Optimization Tips
+
+1. Keep source images below 8192x8192 for best performance
+2. Use JPEG thumbnail format for smaller file sizes
+3. Adjust thumbnail quality vs file size tradeoff with `thumbnail_quality`
+
+## Error Handling
+
+The plugin handles:
+- **Corrupted Files**: Returns descriptive error
+- **Unsupported Variants**: Gracefully skips unsupported HEIF features
+- **Memory Limits**: Fails safely if image too large
+- **Timeout**: Returns error if processing exceeds CPU time limit
+
+## Testing
+
+```bash
+# Run unit tests
+cargo test
+
+# Test with sample HEIF files
+cargo test --test integration -- --nocapture
+```
+
+## Troubleshooting
+
+### Plugin Fails to Load
+
+- Check that `heif_support.wasm` exists in plugin directory
+- Verify `plugin.toml` is valid TOML
+- Check Pinakes logs for detailed error messages
+
+### Thumbnails Not Generated
+
+- Verify `generate_thumbnails = true` in config
+- Check filesystem write permissions for thumbnail directory
+- Ensure source image is below size limits
+
+### Out of Memory Errors
+
+- Reduce `max_width` and `max_height` in config
+- Increase `max_memory_mb` if source images are large
+- Check that source files aren't corrupted
+
+## Future Enhancements
+
+- Support for HEIF image sequences (burst photos)
+- HDR metadata extraction
+- Live Photo support
+- AVIF format support (similar to HEIF)
+
+## License
+
+MIT