WIP: lift light surfaces and neutralize chrome hover/focus

[zacknelson]

Summary

• Initial theme steering pass for Emre to glance at. Light surfaces are lifted and the elevation ramp is compressed; light shadows are quieter; content sidebars sit on surfaceRaised.
• Brand crimson is pulled off chrome jobs (field focus, list hover, keyboard outlines, search, dropdown open state, grid hover/selection/resize, column names). Tabs, notebook cell focus, notebook title glyphs, AI composer, and login stay branded.
• Decision log is in THEME-STEERING.md (status: applied locally). THEMING.md is untouched.

This is still WIP — checkboxes/switches and a few leftover brand bindings are deferred, and palette values will keep moving.

Test plan

• Light mode: notebook, SQL editor, details drawer, schema tree, editor search, result grid (headers, row hover, selection, column resize)
• Dark mode glance: same surfaces still read; grid selection/focus ring still visible
• Confirm branded leftovers still look intentional: tab underlines, notebook cell ring, notebook glyph, AI composer, login, SelectMenu checkmarks
• Keyboard focus rings are slate (borderStrong), not crimson

Made with Cursor