Fix: Prevent premature state update and export corruption in TrimControl

[Sandeep6135]

Description

This pull request fixes a critical state corruption bug in the video trimming workflow.
The Problem:
Previously, the handleEnd function in TrimControl updated the global recipe.trimEnd state before validating the user's input. If a user entered an invalid value (resulting in NaN) or an out-of-bounds value, the NaN value was committed to the state despite the UI showing an error. This bypassed the pre-export validation (NaN > duration evaluates to false), passing corrupted state to FFmpeg and causing the video export to fail/crash.
The Solution:
Moved the onChange({ trimEnd: n }) state dispatch to the very end of the handleEnd function. The global recipe state is now only updated after all input validation checks (like isNaN, positive integer bounds, and duration checks) pass successfully.
Testing:

• Verified that entering invalid characters correctly shows an inline error without persisting to the global recipe.
• Verified that valid inputs successfully update the state.
• Verified that corrupted values no longer bypass the export validations.

Closes #954

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