refactor(web): dashboard typography & contrast pass

Removes the global `uppercase` + `font-mondwest` from the App.tsx root
that forced every page to opt-out, replaces stacked-alpha text colors
with semantic tokens for WCAG-AA contrast across all 7 themes, and
applies the new `text-display` utility from @nous-research/ui@0.16.0
on intentional brand chrome (page titles, sidebar headings, segmented
filters) only. Bumps every sub-12px arbitrary text size to text-xs.

Also widens the dashboard plugin routes (/api/dashboard/agent-plugins/
{name:path}/...) so category-namespaced plugins like observability/
langfuse and image_gen/openai can be enable/disabled from the dashboard
— previously the FE encodeURIComponent-ed the slash and the backend
{name} route rejected it. _validate_plugin_name still blocks .. and
backslash, and strips leading/trailing slash.

Touches sessions/env/keys page chrome and adds two new i18n keys
(`overview`, `showMore`/`showLess`) across all 18 locales.

Squashes 19 commits from PR #28832.

Co-authored-by: Hermes <noreply@nousresearch.com>

web/src/App.tsx

@@ -326,7 +326,9 @@ export default function App() {
     api
       .getConfig()
       .then((cfg) => {
-        const dash = (cfg?.dashboard ?? {}) as { show_token_analytics?: unknown };
+        const dash = (cfg?.dashboard ?? {}) as {
+          show_token_analytics?: unknown;
+        };
         setShowTokenAnalytics(dash.show_token_analytics === true);
       })
       .catch(() => setShowTokenAnalytics(false));
@@ -366,7 +368,9 @@ export default function App() {
     const base = embeddedChat
       ? [CHAT_NAV_ITEM, ...BUILTIN_NAV_REST]
       : BUILTIN_NAV_REST;
-    return showTokenAnalytics ? base : base.filter((n) => n.path !== "/analytics");
+    return showTokenAnalytics
+      ? base
+      : base.filter((n) => n.path !== "/analytics");
   }, [embeddedChat, showTokenAnalytics]);
 
   const sidebarNav = useMemo(
@@ -416,7 +420,7 @@ export default function App() {
   return (
     <div
       data-layout-variant={layoutVariant}
-      className="font-mondwest flex h-dvh max-h-dvh min-h-0 flex-col overflow-hidden bg-black uppercase text-midground antialiased"
+      className="flex h-dvh max-h-dvh min-h-0 flex-col overflow-hidden bg-black text-text-primary antialiased"
     >
       <SelectionSwitcher />
       <Backdrop />
@@ -442,7 +446,7 @@ export default function App() {
           aria-label={t.app.openNavigation}
           aria-expanded={mobileOpen}
           aria-controls="app-sidebar"
-          className="text-midground/70 hover:text-midground"
+          className="text-text-secondary hover:text-midground"
         >
           <Menu />
         </Button>
@@ -498,7 +502,7 @@ export default function App() {
                 <PluginSlot name="header-left" />
 
                 <Typography
-                  className="font-bold text-[1.125rem] leading-[0.95] tracking-[0.0525rem] text-midground"
+                  className="font-bold text-[1.125rem] leading-[0.95] tracking-[0.0525rem] text-midground uppercase"
                   style={{ mixBlendMode: "plus-lighter" }}
                 >
                   Hermes
@@ -512,7 +516,7 @@ export default function App() {
                 size="icon"
                 onClick={closeMobile}
                 aria-label={t.app.closeNavigation}
-                className="lg:hidden text-midground/70 hover:text-midground"
+                className="lg:hidden text-text-secondary hover:text-midground"
               >
                 <X />
               </Button>
@@ -542,7 +546,7 @@ export default function App() {
                   <span
                     className={cn(
                       "px-5 pt-2.5 pb-1",
-                      "font-mondwest text-[0.6rem] tracking-[0.15em] uppercase opacity-30",
+                      "font-mondwest text-display text-xs tracking-[0.12em] text-text-tertiary",
                     )}
                     id="hermes-sidebar-plugin-nav-heading"
                   >
@@ -671,10 +675,12 @@ function SidebarNavLink({ closeMobile, item, t }: SidebarNavLinkProps) {
           cn(
             "group relative flex items-center gap-3",
             "px-5 py-2.5",
-            "font-mondwest text-[0.8rem] tracking-[0.12em]",
+            "font-mondwest text-display uppercase text-sm tracking-[0.12em]",
             "whitespace-nowrap transition-colors cursor-pointer",
             "focus-visible:outline-none focus-visible:ring-1 focus-visible:ring-midground",
-            isActive ? "text-midground" : "opacity-60 hover:opacity-100",
+            isActive
+              ? "text-midground"
+              : "text-text-secondary hover:text-midground",
           )
         }
         style={{
@@ -746,7 +752,7 @@ function SidebarSystemActions({ onNavigate }: { onNavigate: () => void }) {
       <span
         className={cn(
           "px-5 pt-0.5 pb-0.5",
-          "font-mondwest text-[0.6rem] tracking-[0.15em] uppercase opacity-30",
+          "font-mondwest text-display text-xs tracking-[0.12em] text-text-tertiary",
         )}
       >
         {t.app.system}
@@ -772,12 +778,12 @@ function SidebarSystemActions({ onNavigate }: { onNavigate: () => void }) {
                 active={busy}
                 className={cn(
                   "gap-3 px-5 py-1.5 whitespace-nowrap",
-                  "font-mondwest text-[0.75rem] tracking-[0.1em]",
-                  "transition-opacity",
+                  "font-mondwest text-display text-xs tracking-[0.1em]",
+                  "transition-colors",
                   busy
-                    ? "text-midground opacity-100"
-                    : "opacity-60 hover:opacity-100",
-                  "disabled:opacity-30",
+                    ? "text-midground"
+                    : "text-text-secondary hover:text-midground",
+                  "disabled:text-text-disabled",
                 )}
               >
                 {isPending ? (