fix(gui): prevent composer overflow with long unbroken strings

[KHARSHAVARDHAN-eng]

Summary

Fixes composer layout overflow when typing or pasting long unbroken strings.

Changes

• Allow long unbroken strings to wrap inside the TipTap editor.
• Prevent the editor flex item from expanding beyond its container by applying min-w-0.

Verification

• Manually verified long unbroken strings wrap correctly.
• Composer width remains stable.
• Send button remains aligned.
• Normal text input behavior is unchanged.
• Responsive sidebar layout behaves correctly.

Notes

Automated tests could not be fully executed because the local environment did not have all required project dependencies installed.

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