Date / Time formatting inconsistent

[TomberWolf]

Unfortunately, there are some inconsistencies regarding time and date formats.
Some elements do not appear to follow the browser's locale format.

It would be great if this could be adjusted accordingly so that it aligns consistently with local formats.
I'm running v0.13.2 (rust)

Example:

[TimeToBuildBob]

Tracked the locale inconsistency to aw-webui rather than the Rust server layer and opened the frontend fix here: ActivityWatch/aw-webui#825.

What it changes:

• removes hardcoded English weekday labels in TimelineBarChart
• replaces the English ordinal/month label paths with locale-aware helpers
• adds a focused unit test (npm test -- --runInBand test/unit/time.test.js)

Because aw-server-rust vendors aw-webui as a submodule, landing the UI fix in aw-webui first is the clean path. After that merges, the remaining aw-server-rust step is just the normal submodule bump.