feat: Forge design system app-wide + Stacks i18n

Promotes the Forge visual language from the Stacks feature into a
global design system used across the app:

- app.css: Forge utilities (dot-grid backdrop, eyebrow, ember,
  display/lede, status pills, stat grid, panels, registration
  marks, alert, terminal, buttons). CSS variables alias the forge
  display font to the app's standard sans stack (Inter, now
  properly self-hosted via @fontsource/inter).
- +layout.svelte: reskinned sidebar brand, active nav rail,
  mobile top bar, global h1/h2 typography overrides, main dot-grid
  backdrop.
- Shared components reskinned: EmptyState (breathing-ember empty
  mark), StatusBadge (mono pills with pulse), ConfirmDialog
  (registration marks + forge buttons).
- Dashboard (+page.svelte): ForgeHero header, forge-stat-grid,
  Instrument-style section titles with accent.
- New ForgeHero component for reusable hero headers.

Stacks feature fully localized (EN + RU):
- 80+ keys under stacks.* covering list, new, detail, revisions,
  logs, errors, status labels, delete/rollback dialogs.
- Russian uses forge vocabulary (куются/наковальня/куём/etc).
- $t() wired through all three Stacks pages.

web/package-lock.json

@@ -9,6 +9,7 @@
       "version": "0.1.0",
       "dependencies": {
         "@fontsource/instrument-serif": "^5.2.8",
+        "@fontsource/inter": "^5.2.8",
         "@fontsource/jetbrains-mono": "^5.2.8"
       },
       "devDependencies": {
@@ -447,6 +448,14 @@
         "url": "https://github.com/sponsors/ayuhito"
       }
     },
+    "node_modules/@fontsource/inter": {
+      "version": "5.2.8",
+      "resolved": "https://registry.npmjs.org/@fontsource/inter/-/inter-5.2.8.tgz",
+      "integrity": "sha512-P6r5WnJoKiNVV+zvW2xM13gNdFhAEpQ9dQJHt3naLvfg+LkF2ldgSLiF4T41lf1SQCM9QmkqPTn4TH568IRagg==",
+      "funding": {
+        "url": "https://github.com/sponsors/ayuhito"
+      }
+    },
     "node_modules/@fontsource/jetbrains-mono": {
       "version": "5.2.8",
       "resolved": "https://registry.npmjs.org/@fontsource/jetbrains-mono/-/jetbrains-mono-5.2.8.tgz",
@@ -2300,6 +2309,11 @@
       "resolved": "https://registry.npmjs.org/@fontsource/instrument-serif/-/instrument-serif-5.2.8.tgz",
       "integrity": "sha512-s+bkz+syj2rO00Rmq9g0P+PwuLig33DR1xDR8pTWmovH1pUjwnncrFk++q9mmOex8fUQ7oW80gPpPDaw7V1MMw=="
     },
+    "@fontsource/inter": {
+      "version": "5.2.8",
+      "resolved": "https://registry.npmjs.org/@fontsource/inter/-/inter-5.2.8.tgz",
+      "integrity": "sha512-P6r5WnJoKiNVV+zvW2xM13gNdFhAEpQ9dQJHt3naLvfg+LkF2ldgSLiF4T41lf1SQCM9QmkqPTn4TH568IRagg=="
+    },
     "@fontsource/jetbrains-mono": {
       "version": "5.2.8",
       "resolved": "https://registry.npmjs.org/@fontsource/jetbrains-mono/-/jetbrains-mono-5.2.8.tgz",