Add support for HEIC/HEIF, GIF, and MOV formats with FFmpeg integration

[SmilyOrg]

Introduce support for HEIC, HEIF, GIF, and MOV formats, enhancing media compatibility. FFmpeg integration allows for decoding these formats, which are commonly used on iOS devices. The default configuration now includes these extensions for automatic indexing and display in Photofield.

Contributes to #52

[Copilot]

Pull request overview

Adds default indexing + HTTP serving support for common iOS-related formats (HEIC/HEIF and Live Photo MOV) plus GIF, relying on FFmpeg for decoding when available. Contributes to #52 (iOS Live Photo support).

Changes:

• Register additional MIME types for .heic, .heif, .gif, and .mov.
• Extend default config to index/recognize HEIC/HEIF/GIF images and MOV videos.
• Update runtime/dependency docs and Docker image dependencies; add an unreleased changelog entry.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
main.go	Adds MIME mappings for HEIC/HEIF/GIF/MOV.
docs/dependencies.md	Documents FFmpeg as the dependency enabling these formats (with version guidance).
defaults.yaml	Adds .heic, .heif, .gif, .mov to default indexed extensions and image/video extension lists.
Dockerfile	Updates Alpine base and documents/install runtime deps including FFmpeg.
.changes/unreleased/heic-support.md	Adds unreleased changelog entry announcing the new format support.

[Copilot]

These new MIME registrations are inside if apiPrefix != "/" (the UI+API mode). In apiPrefix == "/" (API-only) mode they won’t run, so http.ServeFile for originals (e.g., /files/{id}) may still respond with application/octet-stream for HEIC/HEIF/GIF/MOV. Consider moving the relevant mime.AddExtensionType calls outside this conditional (or duplicating them for API-only) so content-types are correct in both modes.

[Copilot]

The FFmpeg version guidance here ("8.0.1+ includes HEVC decoder") doesn’t match the docs (which recommend v7.0+) and may be inaccurate since HEVC support depends on how FFmpeg is built (codecs enabled), not just the version. Consider rewording to describe the required codec support (HEVC/H.265 + libheif) and keeping version recommendations consistent across docs and Dockerfile comments.

Suggested change

	# - ffmpeg: video thumbnails, HEIC/HEIF/MOV/GIF support (8.0.1+ includes HEVC decoder)
	# - ffmpeg: video thumbnails, HEIC/HEIF/MOV/GIF support (requires build with HEVC/H.265 decoder + libheif; FFmpeg 7.0+ recommended, see docs)

[Copilot]

This adds a specific FFmpeg version recommendation, but the Dockerfile comment references a different version. Consider keeping version guidance consistent across the repo (or avoiding a specific version and instead documenting the required codec support for HEIC/HEIF/MOV).

Suggested change

	- [FFmpeg]: Generates video thumbnails and previews and adds support for more image formats including HEIC/HEIF (iOS photos), MOV (QuickTime videos), and basic RAW formats. **(v7.0+ recommended)**
	- [FFmpeg]: Generates video thumbnails and previews and adds support for more image formats including HEIC/HEIF (iOS photos), MOV (QuickTime videos), and basic RAW formats.

[Copilot]

The first sentence says these formats are "fully supported", but the next sentence makes support conditional on FFmpeg being available. Consider rephrasing to avoid implying unconditional support (e.g., "supported when FFmpeg is installed/available").

Suggested change

HEIC (High Efficiency Image Container), HEIF (High Efficiency Image Format), GIF, and MOV (QuickTime) files are now fully supported. These formats, commonly used by iOS devices and other platforms, are decoded using FFmpeg when available. The extensions `.heic`, `.heif`, `.gif`, and `.mov` are now included in the default configuration, so Photofield will automatically index and display these files alongside your other media.

HEIC (High Efficiency Image Container), HEIF (High Efficiency Image Format), GIF, and MOV (QuickTime) files are now supported when FFmpeg is available. These formats, commonly used by iOS devices and other platforms, are decoded using FFmpeg. The extensions `.heic`, `.heif`, `.gif`, and `.mov` are now included in the default configuration, so Photofield will automatically index and display these files alongside your other media when FFmpeg is installed.

[SmilyOrg]

@copilot open a new pull request to apply changes based on the comments in this thread

[Copilot]

@SmilyOrg I've opened a new pull request, #172, to work on those changes. Once the pull request is ready, I'll request review from you.