[datlechin]

Why

Under a custom theme, editable row inspector values drew a light system box beside themed read-only and multi-line values. A rounded bezel paints its own fill and edits in the window's shared field editor, so no theme color reaches it. A few other surfaces still bypassed the theme carriers.

Change

• Editable inspector values, the editable hex field and array popover elements use a new ValueTextField: a borderless field filling the value well, with the system focus ring and its own field editor on the theme's caret and selection. Text replacement no longer rewrites typed values.
• Under the default themes these values and the read-only hex dump now sit in the value well too, so editable and read-only values match.
• Users & Roles bars and the file conflict captions follow the themed backdrop. Filter and chart bars no longer reach under the macOS 26 toolbar.
• Removed the second diagram canvas backdrop, the status bar opt-out flag, three more copies of the macOS 26 gate and unused theme API.

Verified

InspectorValueThemeTests.editableValueTakesTheEditorBackground fails on main and passes here. Changed on purpose: dumpDefaultHasNoWell and StatusBarChromeTests. Removed: canvasBackdropFollowsTheTheme, otherBarsKeepTheirMaterial.

Screenshots

Tokyo Night, row inspector, before and after:

Whole window, after:

Not in this PR

• SwiftUI Tables in Users & Roles and Compare stay chrome (theme.md).
• SchemaTextFieldView stays a bezel with text replacement on.
• Multi-line value wells have no focus ring.