Split Tasks screen into definitions + flat runs

[oandregal]

Summary

• Restructure the Tasks screen (and the project sidebar Tasks tab) into two clear visual zones: task definition cards at the top, and a unified flat "Runs" list below
• Active runs sort to the top naturally; there's no longer a separate "Running" section
• Run rows are now borderless with a hover background, making them visually lighter than definition cards
• Timestamp moved next to the status badge ("DONE · finished 2d ago"), removing the third meta line
• Renamed "Run now" to "Run" on definition cards
• Removed the "Your tasks" section header

Test plan

• Verify the Tasks screen shows definition cards (with border) at the top, flat run rows below
• Verify active runs appear at the top of the Runs list with a progress bar and Stop button
• Verify completed runs appear below active runs with correct status + timestamp
• Verify the project sidebar Tasks tab shows the same two-section layout
• Verify hovering a run row shows a subtle background highlight
• Verify the "Run" button on definition cards triggers the task

🤖 Generated with Claude Code