feat(qol): add Forever swing timer

[dfrisone]

What does this PR do?

Adds an optional Quality of Life swing timer with separately configurable main-hand, off-hand, and ranged bars. It uses the client-provided player swing event and native duration rendering. The feature is disabled by default and removes its event registrations, visible frames, and duration bindings when disabled.

How was it tested?

• Passed the offline lifecycle harness for disabled startup, enable/disable cleanup, native duration routing, restricted-value guards, queue display, weapon changes, Unlock Mode positioning, and frame reuse.
• Added and passed a regression case where the initial main-hand attack speed is opaque; the Main Hand row remains visible before the first attack event.
• Passed the diff-scoped style gate, whitespace check, and locale-key extraction.
• In-game validation has not been run by Codex.

Screenshots

Checklist

• New settings default OFF (no behavior change without opt-in)
• Zero cost while disabled: no events registered, no polling, no hooks doing work, no frames built
• Cheap while enabled: event-driven (no polling, no timer-based logic, no per-frame allocations)
• No writes onto Blizzard-owned frames (weak-table pattern used); HookScript/hooksecurefunc only, never SetScript on Blizzard frames
• Tested in-game on live; no version gates or pre-Midnight APIs added (unverified: no in-game test)

[dfrisone]

Already upstream: this landed as EllesmereGaming#2128 on 2026-09-19. The branch has no commits that are not in upstream/main, so there is nothing left to submit.