fix(eidos): THEME-SYS-2 — dropdown/context-menu disabled items use --opacity-disabled

`item-disabled-opacity` hardcoded `0.55`, off the framework's canonical disabled
opacity (`--opacity-disabled` = 0.4, used by Dialog and others). dropdown-menu +
context-menu now reference the token — disabled menu items match every other
disabled surface. Browser-verified: the resolved token is 0.4.

Scoped to the disabled-opacity drift only. The other THEME-SYS-2 candidates are
left as justified non-drift: `overlay-opacity 62%` / calendar `day-outside 0.62`
are off-scale (no `--opacity-62`; the 0.05-step scale has no slot) named recipe
tokens — a deliberate scrim density, which the off-scale doctrine permits; and
select `item-description-font-size 0.85em` is a RELATIVE unit with no absolute
`--font-size-*` equivalent.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/uix/eidos/generated/base.css

@@ -3422,7 +3422,7 @@
 	--dropdown-menu-item-radius: var(--radius-sm);
 	--dropdown-menu-item-bg-hover: var(--color-primary-element);
 	--dropdown-menu-item-fg-hover: var(--color-content-primary);
-	--dropdown-menu-item-disabled-opacity: 0.55;
+	--dropdown-menu-item-disabled-opacity: var(--opacity-disabled);
 	--dropdown-menu-heading-px: var(--space-2);
 	--dropdown-menu-heading-py: var(--space-1);
 	--dropdown-menu-heading-font-size: var(--font-size-xs);
@@ -3440,7 +3440,7 @@
 	--context-menu-item-radius: var(--radius-sm);
 	--context-menu-item-bg-hover: var(--color-primary-element);
 	--context-menu-item-fg-hover: var(--color-content-primary);
-	--context-menu-item-disabled-opacity: 0.55;
+	--context-menu-item-disabled-opacity: var(--opacity-disabled);
 	--context-menu-heading-px: var(--space-2);
 	--context-menu-heading-py: var(--space-1);
 	--context-menu-heading-font-size: var(--font-size-xs);

src/uix/eidos/lib/recipes/base.ts

@@ -4291,7 +4291,7 @@ export const THEME_BASE_RECIPE_TOKENS = {
 		'item-radius': 'var(--radius-sm)',
 		'item-bg-hover': 'var(--color-primary-element)',
 		'item-fg-hover': 'var(--color-content-primary)',
-		'item-disabled-opacity': '0.55',
+		'item-disabled-opacity': 'var(--opacity-disabled)',
 		'heading-px': 'var(--space-2)',
 		'heading-py': 'var(--space-1)',
 		'heading-font-size': 'var(--font-size-xs)',
@@ -4315,7 +4315,7 @@ export const THEME_BASE_RECIPE_TOKENS = {
 		'item-radius': 'var(--radius-sm)',
 		'item-bg-hover': 'var(--color-primary-element)',
 		'item-fg-hover': 'var(--color-content-primary)',
-		'item-disabled-opacity': '0.55',
+		'item-disabled-opacity': 'var(--opacity-disabled)',
 		'heading-px': 'var(--space-2)',
 		'heading-py': 'var(--space-1)',
 		'heading-font-size': 'var(--font-size-xs)',