UI improvements for sketch/shape lists and coding style guidance

[trailcode]

Summary

• Make Sketch List selection switch GUI into Sketch_inspection_mode.
• Improve Sketch List and Shape List behavior in narrow panes (horizontal-scroll content and aligned name-field width handling).
• Refactor shared list name-width logic into GUI::list_name_field_width_.
• Update style docs and Cursor rule guidance for reader-first .cpp organization, helper placement near use, and pragmatic DRY guidance.
• Add issue drafts for branch context and follow-up tracking.

Files Changed

• src/gui.cpp
• src/gui.h
• src/gui_settings.cpp
• ezycad_code_style.md
• .cursor/rules/ezycad_code_style.mdc
• agents/issues/003-ui-improvements-sketch-shape-lists-and-style.md

Related

• Issue: UI improvements: Sketch/Shape list behavior and coding-style guidance #98
• Compare: main...Trailcode/ui_improvements

Test Plan

• Build EzyCad_lib in Release config.
• In Sketch List, click a sketch row selector and verify mode becomes sketch inspection.
• Resize Sketch List very narrow and verify controls remain reachable via horizontal scroll.
• Resize Shape List very narrow and verify controls remain reachable via horizontal scroll.
• Rename sketches and shapes with short and long names; verify input widths are usable and consistent.
• Verify no ImGui ID-stack warnings appear while interacting with both lists.

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Note

Low Risk
Low risk UI-focused changes; main behavior change is auto-switching to Sketch_inspection_mode when selecting a sketch, which could affect user workflow but doesn’t touch persistence or core geometry logic.

Overview
Improves list-pane usability by making Sketch List selection automatically switch to Mode::Sketch_inspection_mode, and by adding horizontal scrolling plus consistent, capped name input widths in both Sketch and Shape lists via shared GUI::list_name_field_width_.

Tightens a small settings path by asserting sketches are non-null before updating underlay tint, and updates ezycad_code_style.md with reader-first .cpp organization, local declaration placement, and pragmatic DRY guidance. Adds draft issue/PR markdowns for tracking follow-ups.

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