Extract hardcoded window size constraints to named constants

[Copilot]

Addresses review feedback on #5 to eliminate magic numbers for minimum window dimensions (300px width, 200px height) repeated across resize logic.

Changes

• Added MIN_WINDOW_WIDTH and MIN_WINDOW_HEIGHT constants to src/constants/index.js
• Updated WindowWrapper.jsx to import and use these constants instead of hardcoded values (6 occurrences replaced)

// Before
newWidth = Math.max(300, startWidth + (e.clientX - startX));
if (newWidth > 300) newLeft = startLeft + delta;

// After
newWidth = Math.max(MIN_WINDOW_WIDTH, startWidth + (e.clientX - startX));
if (newWidth > MIN_WINDOW_WIDTH) newLeft = startLeft + delta;

Window resize constraints now centralized in constants file for consistent updates.

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