feat: refine opened note spacing and card transition

[fjbarrett]

Summary

Opened notes now have a 22-point semibold title and approximately 30-point text insets, with the existing body reading size preserved. The dark material matches the near-black charcoal of the grid cards.

Title and body state are initialized from the current draft or saved note before presentation, avoiding a text-layout change during the native card expansion. Existing autosave, close, color, and keyboard behavior remain intact.

Test plan

• Regenerated projects; KeepMac, signed iPhone, and SE simulator fixture builds passed.
• Inspected light and dark layouts, wrapping titles, and the largest accessibility text size on the SE simulator. Recorded the full card expansion and return; runtime logs contain no nil-source transition fallback warning.
• Created and reopened a fixture note with an explicit title and body; verified autosave completed while the editor stayed open and no pending draft files remained.
• Existing native and web CI checks passed. No new tests for this small presentation change.
• Build 20260905.378 is installed on the physical SE and its version verified. The clean retained Xcode project matches the merged source. Launch succeeded after unlock; live PID 57642 matches the installed build 378 app container.

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