build(eslint): drop the Z_RAW and EDGED_LABEL selectors

Both came out of the E28 claim audit (0521149c named z-levels, e13d93a3
static labels as flat Badges) after the audit itself had fixed the sites.
No real hit since: 0 matches in every lint run from E28 to E34 (S2/S3
measurement). Each still cost a probe test (zLayer.contract, the edged-label
half of hoverAndLink.contract) and a place in the gate snapshot. The design
rules stay in DESIGN.md (Tokens: no ad-hoc z-index; Static vs pressable),
with a decision-log row saying the selectors went and why.

frontend/src/lib/gates.snapshot.json

@@ -870,14 +870,6 @@
               "message": "px-frozen box size doesn't scale with --font-scale: give a grid column's minimum in rem (minmax(9.375rem,1fr)), not minmax(Npx,…).",
               "selector": "TemplateElement[value.raw=/minmax\\([\\d.]+px,/]"
             },
-            {
-              "message": "z-index off the layer scale: use a named level (z-under, z-base, z-menu, z-chrome, z-panel, z-rail, z-overlay, z-popover, z-tooltip), not z-N or z-[…].",
-              "selector": "Literal[value=/(^|[\\s:])-?z-([1-9]\\d*|\\[[^\\]]+\\])(?![\\w-])/]"
-            },
-            {
-              "message": "z-index off the layer scale: use a named level (z-under, z-base, z-menu, z-chrome, z-panel, z-rail, z-overlay, z-popover, z-tooltip), not z-N or z-[…].",
-              "selector": "TemplateElement[value.raw=/(^|[\\s:])-?z-([1-9]\\d*|\\[[^\\]]+\\])(?![\\w-])/]"
-            },
             {
               "message": "hover by a colour swap: use the B3 layer (`state-layer`, Pressable `layer`, `state-filled` on a fill), not hover:bg-card / bg-border / opacity-N.",
               "selector": "Literal[value=/(^|[\\s:])hover:(bg-(card|border|surface|muted)(?![\\w-])|bg-\\(--(hover|press)\\)|opacity-)/]"
@@ -893,14 +885,6 @@
             {
               "message": "a palette colour: use a semantic token (text-rating, bg-live, bg-media-chrome, text-danger, …; DESIGN.md Tokens), not text-amber-500.",
               "selector": "TemplateElement[value.raw=/(^|[\\s:])(text|bg|border|fill|stroke|from|via|to|ring|outline|decoration|divide|caret|shadow)-(red|orange|amber|yellow|lime|green|emerald|teal|cyan|sky|blue|indigo|violet|purple|fuchsia|pink|rose|slate|gray|zinc|neutral|stone)-\\d/]"
-            },
-            {
-              "message": "a static label with an edge reads as a pressable chip: use ui/Badge (flat, tonal) for a label that does nothing.",
-              "selector": "JSXOpeningElement[name.name='span'] JSXAttribute[name.name='className'] Literal[value=/^(?=.*(^|\\s)rounded-(full|md|lg|xl|2xl)(\\s|$))(?=.*(^|\\s)border(\\s|$))/]"
-            },
-            {
-              "message": "a static label with an edge reads as a pressable chip: use ui/Badge (flat, tonal) for a label that does nothing.",
-              "selector": "JSXOpeningElement[name.name='span'] JSXAttribute[name.name='className'] TemplateElement[value.raw=/^(?=.*(^|\\s)rounded-(full|md|lg|xl|2xl)(\\s|$))(?=.*(^|\\s)border(\\s|$))/]"
             }
           ],
           "no-self-assign": [2, { "props": true }],
@@ -1520,8 +1504,7 @@
         "src/lib/useUrlMirror.dom.test.ts",
         "src/lib/verifyEntry.dom.test.tsx",
         "src/lib/viewportUnits.contract.test.ts",
-        "src/lib/vocab.dom.test.ts",
-        "src/lib/zLayer.contract.test.ts"
+        "src/lib/vocab.dom.test.ts"
       ],
       "lib/api/core.ts": ["src/lib/api/core.ts"],
       "lib/http.ts": ["src/lib/http.ts"],