Fix: TargetFrameRate setter used stale value and ignored vsync

[AshishT112203]

Closes #59.

Two distinct bugs in the FPS settings path:

Bug A — TargetFrameRate setter used a stale backing-field value

The setter assigned Program.main.DrawRateLimiterTarget = S_TargetFrameRate before storing the new value into S_TargetFrameRate, so the limiter target was always one step behind the slider. Also unconditionally set UseDrawRateLimiter = true, ignoring vsync. Rewrote to store value first, use Math.Max(S_TargetFrameRate, 60) for parity with InitalizeFPSThings(), and respect UncappedFPS.

Bug B — Rate limiter disabled at startup when vsync is on

InitalizeFPSThings() set UseDrawRateLimiter = !UseVSync && UncappedFPS && TargetFrameRate >= 60 — explicitly disabling the limiter when vsync is on, trusting vsync alone to cap FPS. On the reporter's setup (and likely many others — adaptive sync / G-Sync / FreeSync / certain windowed configs), vsync silently fails to actually cap and the user sees 3000+ FPS at startup.

The reporter's existing workaround — "nudge the slider 240 → 180 → 240" — works precisely because the buggy TargetFrameRate setter force-enabled the rate limiter. We make the rate limiter a safety net on the load path too: enabled whenever UncappedFPS && TargetFrameRate >= 60, regardless of vsync. UseVSync setter updated to match so the three apply paths (UseVSync setter, TargetFrameRate setter, InitalizeFPSThings) all use the same calculation.

Also updated the V-Sync menu description (which said it "overrides FPS Target") and fixed the "Verticaly" typo while there.

Note: with this PR, FPS Target and V-Sync coexist (lower cap wins) instead of vsync overriding the target. For users on working-vsync setups, this is a no-op unless they set FPS Target lower than their refresh rate. If you'd prefer to keep the existing semantics and address #59 a different way (e.g. log when ApplyChanges() fails to honor vsync), happy to rework.

Test plan

• Builds clean (~200 warnings as expected, no new ones)
• Set FPS Target = 240, restart with V-Sync ON → cap holds at 240 (was 3000+)
• Set FPS Target = 240, restart with V-Sync OFF → cap holds at 240
• Set FPS Target = 0, restart → uncapped (limiter disabled)
• Set FPS Target = 240 → 180 → 240 live without restart → cap follows slider exactly each step