docs: Update CLAUDE.md with Issue #4 completion

- Mark Issue #4 (Layout Max-Width) as complete
- Add Issue #5 (Temperature Ranges) as next up

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

CLAUDE.md

@@ -129,8 +129,8 @@ This is a fork with UX improvements. Issues are tracked on the Gitea instance ab
 | 1 | Inline Creation Modals | ✅ DONE |
 | 2 | Smart Density Defaults | ✅ DONE |
 | 3 | QR Code Sizing Fixes | ✅ DONE |
-| 4 | Layout Max-Width | 🔄 NEXT |
-| 5 | Temperature Ranges | Open |
+| 4 | Layout Max-Width | ✅ DONE |
+| 5 | Temperature Ranges | 🔄 NEXT |
 | 6 | Spool Adjustment History | Open |
 | 7 | 3dfilamentprofiles Integration | Open |
 
@@ -175,9 +175,19 @@ Files modified:
 - `client/src/pages/printing/printing.tsx` - Added settings to interface
 - `client/src/pages/printing/qrCodePrintingDialog.tsx` - CSS and UI controls
 
-### Issue #4 Next - Layout Max-Width
+### Issue #4 Complete - Layout Max-Width
+
+Changes:
+- Added 1400px max-width container in `SpoolmanLayout`
+- Added 800px max-width for forms via CSS override in `overrides.css`
+- Content is centered on wide screens
+
+### Issue #5 Next - Temperature Ranges
 
 Plan:
-- Add max-width constraint to main layout for better UX on wide screens
-- Wrap content with centered container (max ~1400px)
-- Add form max-width (~800px) for better readability
+- Convert single temp values to min/max ranges for better label printing
+- Add new database columns: `settings_extruder_temp_min/max`, `settings_bed_temp_min/max`
+- Create Alembic migration to handle data migration
+- Update API models and endpoints
+- Update frontend forms to use range inputs
+- Update label template to show ranges like "190-210°C"