Allow decimal weight entry and remove last-session chip in workout session logger

[rodrigogiraoserrao]

Motivation

• Allow users to enter free-form decimal weights in the session logger and remove the small per-exercise "last session" label showing previous weight/reps to simplify the UI and avoid redundancy.

Description

• Change the weight input step from 0.5 to any so decimal values of any precision are accepted (weightInput.step = 'any').
• Remove the renderPreviousChip function and the code that appended the per-exercise Last: … kg · … reps chip from renderExercise to drop the small last-session label.
• Keep existing behaviour that still reads previous-set values for pre-filling inputs when available.

Testing

• Ran git diff --check to validate there are no whitespace or diff errors, and it succeeded.

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Codex Task