Feat/mod preset ergonomy

[metasmash]

Features

• Improves the Mod presets manager while keeping the existing modpresets.txt format.
• Shows the current preset state in the Mod Manager header.
• Adds preset actions for selecting, merging, updating, renaming, deleting, and cleaning missing entries.
• Adds per-mod preset actions: add/remove from selected preset and add/remove from all presets.
• Prompts to also add missing dependencies when adding a mod to a preset.
• Adds English, French, and Chinese strings for the new preset UI.
• When we add a mod to the preset, automatically turn it on to reduce CTA

QA / How to test

• Launch Olympus from source and open Manage Installed Mods.
• Confirm the header shows Preset: ....
• Open Mod presets.
• Select a preset and confirm it loads that preset and marks it selected.
• Merge another preset and confirm it adds those mods without replacing the current selection.
• Update, rename, and delete a test preset.
• Use a mod row's Preset button to add/remove it from the selected preset.
• Add a mod with dependencies to a preset and confirm the dependency prompt appears.
• Confirm modpresets.txt still uses the existing text format.

Notes

Given that this update already adds direct preset management actions in the UI, I thought it was no longer necessary to keep a button for opening modpresets.txt manually.

Future possible improvement:

• Globally improve the UX to make usage obvious

I can add those two points to the current PR if you want!