feat: hero carousel CMS + responsive mobile/iPad fix + flat-scope assets

Replaces the filesystem-scan hero (fs.readdirSync of /public/footage/main)
with a fully CMS-driven HeroSlide model. Editors can now drag-drop reorder,
toggle slides on/off, set focal points for proper mobile cropping, and
auto-translate per-slide captions.

NEW SCHEMA (additive — does not touch existing tables)
- HeroSlide: mediaUrl, mediaType, altText, order, isActive, focalPointX,
  focalPointY, translationsJson, timestamps
- SiteSetting: key-value JSON store for site-wide config (favicon, logo,
  footer, OG image) — wired up in next commit
- Migration 20260504120000_add_hero_slides_and_site_settings/migration.sql
  uses CREATE TABLE IF NOT EXISTS, additive only

HERO REEL REFACTOR (Bug #4 — responsive mobile/iPad)
- Switches from `images: string[]` to `slides: HeroSlideData[]` while
  keeping a backwards-compat path so legacy callers still work
- w-screen → w-full max-w-[100vw] (no horizontal scroll on iOS)
- h-[100vh] → h-[100svh] so iOS Safari URL bar doesn't push content
- Reduces title font sizes on small viewports (text-3xl → text-4xl
  → text-5xl → text-[5.5rem]) so the headline stays inside the canvas
- objectPosition driven by focal-point fields per slide
- Native <video> support for video slides

HQ COMMAND — /hq-command/dashboard/hero
- Drag-drop reorder, click-to-set-focal-point, inline alt-text editing
- Auto-save with "Saving…" / "Saved ✓" indicators
- Per-slide caption overrides (title, subtitle, descriptions)
- Optional one-click AI translation to IT, VEC, ES, DE
- Drop-zone uploader → /api/assets (scope=footage, flat folder)

API — /api/assets
- New flat scopes: "footage" (writes to /public/footage/main) and
  "branding" (writes to /public/branding) — slug-less for site-wide assets
- New buildPublicUrl helper centralises the URL convention
- Revalidate helper expanded with branding + settings scopes

HOME PAGE
- Reads hero slides from DB first; falls back to filesystem scan when
  HeroSlide table is empty (so production keeps working immediately
  after migration runs but before the editor populates rows)

DEPLOY NOTES
- After git pull on VPS, run the migration ONCE:
    docker compose exec app npx prisma migrate deploy
  Then:
    docker compose up -d --build app
  Existing data (AdminUser w/ 2FA, ClientUser, GlobalNode, Application,
  TimelineEvent, NewsArticle, HeritageSection, SparePart, OperationsSignal,
  NotificationRoute, PageContent) is NOT touched. Migration only creates
  two new tables.

prisma/migrations/20260504120000_add_hero_slides_and_site_settings/migration.sql

@@ -0,0 +1,35 @@
+-- ─────────────────────────────────────────────────────────────────────────
+-- ADDITIVE MIGRATION — only adds new tables, never modifies or drops.
+-- Existing data (AdminUser, ClientUser w/ 2FA, GlobalNode, etc.) untouched.
+-- ─────────────────────────────────────────────────────────────────────────
+
+-- HeroSlide: carousel slides shown on the home hero section.
+-- Replaces filesystem-scan of /public/footage/main with CMS control.
+CREATE TABLE IF NOT EXISTS "HeroSlide" (
+    "id" TEXT NOT NULL,
+    "mediaUrl" TEXT NOT NULL,
+    "mediaType" TEXT NOT NULL DEFAULT 'image',
+    "altText" TEXT,
+    "order" INTEGER NOT NULL DEFAULT 0,
+    "isActive" BOOLEAN NOT NULL DEFAULT true,
+    "focalPointX" DOUBLE PRECISION NOT NULL DEFAULT 0.5,
+    "focalPointY" DOUBLE PRECISION NOT NULL DEFAULT 0.5,
+    "translationsJson" TEXT DEFAULT '{}',
+    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "updatedAt" TIMESTAMP(3) NOT NULL,
+
+    CONSTRAINT "HeroSlide_pkey" PRIMARY KEY ("id")
+);
+
+-- SiteSetting: key-value config for favicon, logo, footer, OG image, etc.
+CREATE TABLE IF NOT EXISTS "SiteSetting" (
+    "id" TEXT NOT NULL,
+    "key" TEXT NOT NULL,
+    "valueJson" TEXT NOT NULL DEFAULT '{}',
+    "translationsJson" TEXT DEFAULT '{}',
+    "updatedAt" TIMESTAMP(3) NOT NULL,
+
+    CONSTRAINT "SiteSetting_pkey" PRIMARY KEY ("id")
+);
+
+CREATE UNIQUE INDEX IF NOT EXISTS "SiteSetting_key_key" ON "SiteSetting"("key");