feat: sort albums by total size

[Shadi-Alrashoodi]

Description

Adds a "Total size" sort option on the Albums page for web and mobile. Server exposes totalSize on AlbumResponseDto, summed from asset_exif.fileSizeInByte in the existing album metadata query.

• Server: adds totalSize to AlbumResponseDto, aggregated via SUM(asset_exif.fileSizeInByte) in getMetadataForIds.
• Web: adds FileSize to AlbumSortBy and a comparator in album-utils.ts. Table view shows a new Total size column.
• Mobile: adds fileSize to AlbumSortMode (storeIndex 6) and a sort case in remote_album.service.dart.

How Has This Been Tested?

• Updated server unit tests
• Manually verified on web
• Manually verified on mobile

Checklist:

• I have carefully read CONTRIBUTING.md
• I have performed a self-review of my own code
• I have made corresponding changes to the documentation if applicable
• I have no unrelated changes in the PR.
• I have confirmed that any new dependencies are strictly necessary.
• I have written tests for new code (if applicable)
• I have followed naming conventions/patterns in the surrounding code
• All code in src/services/ uses repositories implementations for database calls, filesystem operations, etc.
• All code in src/repositories/ is pretty basic/simple and does not have any immich specific logic (that belongs in src/services/)

Please describe to which degree, if any, an LLM was used in creating this pull request.

Used Claude to navigate the codebase and identify patterns to follow.

[immich-push-o-matic]

Label error. Requires exactly 1 of: changelog:.*. Found: 📱mobile, 🖥️web, 🗄️server. A maintainer will add the required label.

[danieldietzler]

Used Claude to navigate the codebase and identify patterns to follow.

Even the branch name leads with claude/. Are you sure you haven't had Claude just write the entire PR?

[Shadi-Alrashoodi]

No - Claude helped me understand the code and draft parts of it, but I directed the feature, reviewed every change, and tested it myself.

[alextran1502]

Thank you for the PR. I am hesitant to accept this PR, as it could cause performance issues, since it will do a left join with the exif table for all assets in the get albums call.

To better understand the impact, I'd like to get the request time difference between main and this PR for 500 albums, with 1500 assets per album.

Can you help me get that?