Swing Timer: spark width, overhang and per-weapon colors

[necessaryisgoat]

What does this PR do?

The Swing Timer's Show Spark toggle gets a Spark cog:

• Width: the spark's width (default 8, the size every EUI spark already uses).
• Overhang: how far the spark reaches past the bar's top and bottom, in screen pixels (default 0). When the spark overhangs, it moves into its own clip frame, built the first time it's needed, so it's still cut off at the bar's ends.
• Main Hand / Off Hand / Ranged Color: a spark color for each weapon, so each swing is easy to tell apart. Unset, a spark stays white and a combined off hand's spark keeps its fill color.

Existing profiles look the same until one of these is changed.

How was it tested?

Tested in game on the WoW Forever client (the Swing Timer only exists there). .tools/guardrails.py passes.

Screenshots

New cogwheel in the Swing Timer options:

Default Spark (same as before):

Default sizes recolored red (subtle):

Minor overhang (5px red):

15 overhang:

24 overhang (max value lol):

Max width:

Different colors on ranged and melee displayed:

Checklist

• New settings default OFF (no behavior change without opt-in): Width defaults to today's 8, Overhang to 0, and the colors are unset, so the bar looks the same until they're changed.
• Zero cost while disabled: no events registered, no polling, no hooks doing work, no tickers; nothing built beyond an inert event frame or combat queue. The overhang clip frame is only built once Overhang is above 0.
• Cheap while enabled: event-driven (no polling, no timer-based logic, no per-frame allocations). The settings are applied in the look pass only, with nothing per frame.
• No writes onto Blizzard-owned frames (weak-table pattern used); HookScript/hooksecurefunc only, never SetScript on Blizzard frames. Only the Swing Timer's own frames are touched.
• Tested in-game on live; no version gates or pre-Midnight APIs added. Tested on the WoW Forever client, where the Swing Timer runs.