fix: keep notes open on swipe and remove the modal rim

[fjbarrett]

Summary

Existing and new notes now stay open during swipe gestures and close using the existing × button. The editor surface fills its presentation to remove the inset rim; adjusted internal padding preserves text and control positions.

Test plan

• Regenerated projects; KeepMac, signed iPhone, and SE simulator builds passed.
• Verified fast and slow downward gestures and a left-edge swipe keep an existing note open, a downward gesture keeps a new note open, and × returns to the grid.
• Inspected the rim-free surface in light and dark mode; title, body, close, and color positions are preserved. Native card zoom remains active with no nil-source fallback warning.
• Existing native and web CI checks passed. No new tests for this presentation change.
• Physical SE build 20260905.379 installed and launched. App inventory confirms that version, and live PID 57797 matches its installed container. The retained Xcode checkout matches the merged source.

Model: GPT-6
Co-Authored-By: Codex noreply@openai.com