fix(float): don't latch isShowingDebuggerView when the debugger isn't ready

[dimashbk]

Summary

WindowManager.presentDebugger() sets FloatViewManager.isShowingDebuggerView = true before nil-checking floatViewController. The controller is only assigned ~1s after setup() (deferred via asyncAfter in FeatureHandling), so any presentDebugger() call inside that window — a shake handler, a ball tap injected by UI tests — latches the flag with nothing presented and nothing ever resets it:

• the floating ball is hidden by the flag's didSet and never comes back;
• every subsequent presentDebugger() dies on the guard;
• worst of all, CustomWindow.point(inside:) returns true for the whole screen while the flag is set, and isUserInteractionEnabled = false is only applied inside the skipped branch — the invisible window eats every touch and the host app becomes unresponsive until relaunch.

Fix: check floatViewController in the same guard and set the flag only when the debugger is actually presented.

Type of change

• Fix
• Feature
• Refactor
• Docs
• CI/CD

Test plan

• Unit tests updated
• Manual testing completed
• CI passing

Manual test steps

1. Call DebugSwift.App.presentDebugger() within 1s of setup() (e.g. from a shake handler right after launch).
2. Before: ball never appears, later shakes/taps do nothing, app stops responding to touches. After: the early call is a no-op and the debugger works normally once ready.

Checklist

• I reviewed my own changes
• I updated docs when needed
• I considered backward compatibility