chore(eidos): fold tabs trigger hover into the --state-* layer

The last neutral component on a bespoke hover. tabs trigger (transparent base) moves to
the shared state layer:

  background: var(--tabs-trigger-bg-hover)
  -> background-image: linear-gradient(var(--state-hover), var(--state-hover))

Overlay (background-image) keeps it filled-safe for the segmented/pill variant. Removed
the now-orphan --tabs-trigger-bg-hover recipe token + regenerated base.css.

tabs.css is concurrently being reworked by the other session (segmented variant + focus
outline migration, uncommitted). Staged ONLY the hover line via line-level staging
(checkout HEAD + sed the single line) so their uncommitted segmented/focus work stays
untouched + unstaged in the working tree.

Completes the --state-* neutral-hover unification: every neutral component now uses the
state layer; only valenced (palette) hovers keep their own.

Verified: tabs.css uses --state-hover, token gone from base.css, segmented tokens intact;
eidos suite 15 failed (pre-existing) / 255 passed.

src/uix/eidos/components/tabs/tabs.css

@@ -87,7 +87,7 @@
 }
 
 [data-tabs-trigger]:hover {
-	background: var(--tabs-trigger-bg-hover);
+	background-image: linear-gradient(var(--state-hover), var(--state-hover));
 	color: var(--tabs-trigger-color-hover);
 }
 

src/uix/eidos/generated/base.css

@@ -2997,7 +2997,6 @@
 	--tabs-trigger-color-hover: var(--color-content-primary);
 	--tabs-trigger-color-active: var(--color-content-primary);
 	--tabs-trigger-bg: transparent;
-	--tabs-trigger-bg-hover: color-mix( in srgb, var(--color-surface-default) 84%, transparent );
 	--tabs-trigger-bg-active: var(--color-surface-overlay);
 	--tabs-trigger-border: transparent;
 	--tabs-trigger-border-active: var(--color-primary-border);

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

@@ -3552,7 +3552,6 @@ export const THEME_BASE_RECIPE_TOKENS = {
 		'trigger-color-hover': 'var(--color-content-primary)',
 		'trigger-color-active': 'var(--color-content-primary)',
 		'trigger-bg': 'transparent',
-		'trigger-bg-hover': 'color-mix( in srgb, var(--color-surface-default) 84%, transparent )',
 		'trigger-bg-active': 'var(--color-surface-overlay)',
 		'trigger-border': 'transparent',
 		'trigger-border-active': 'var(--color-primary-border)',