## Description:
Replaces the "Highlight small players" on/off toggle with a **0-500%
Strength slider** controlling the glow's **width** (0 = off, 100% = the
previous default).
- `UserSettings`: `highlightSmallPlayers()`/toggle →
`highlightGlowStrength()`/set, float-backed, clamped to [0, 5].
- `SmallPlayerGlowPass` takes the strength via a setter (pushed by
`ClientGameRunner` on the settings-changed event), so it stays a pure
consumer and the slider still updates live while the settings modal has
the sim paused. Width = a non-linear blur-iteration count; intensity
compensated so wider stays about as bright.
- `MapRenderer` persists the strength across a WebGL context restore.
- `SettingsModal`: the toggle row becomes a range input.
Behavior note: with the toggle gone the glow **defaults ON at 100%**
(old toggle defaulted OFF); can default to 0 (opt-in) if preferred.
## Please complete the following:
- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
