fix(detail+docker): per-aspect template preview + Debian frontend base

- Template detail page now shows the render matching the SELECTED aspect (poster +
  preview video) instead of the 16:9 cover cropped into a 9:16/1:1 box. TemplateVariant
  carries per-aspect image/previewVideo; fetchTemplateVariants + the detail page wire them.
- AppShowcase3D ships a distinct preview video per aspect (seed PERASPECT_VIDEO).
- Frontend Dockerfile: Alpine -> node:20-slim (glibc). Fixes next-swc ("ld-linux..."
  load failure that broke `next build` once libc6-compat was removed) AND the original
  CI Alpine-CDN issue. Healthcheck switched to node (slim has no wget).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Dockerfile

@@ -1,9 +1,8 @@
 # ── Stage 1: install dependencies ────────────────────────────────────────────
-FROM mirror.soroushasadi.com/node:20-alpine AS deps
-# NOTE: do NOT `apk add libc6-compat` here — the deps stage only runs `npm ci`
-# (which doesn't need it) and the build/runtime stages omit it anyway. Pulling it
-# reaches Alpine's public CDN (dl-cdn.alpinelinux.org), which is unreachable from
-# the CI server (only the Nexus mirror is) and fails the whole build.
+FROM mirror.soroushasadi.com/node:20-slim AS deps
+# Debian (glibc) base on purpose: Alpine (musl) needs `libc6-compat` for next-swc,
+# which is only on the geo-blocked Alpine CDN (unreachable from the CI server).
+# Debian ships glibc, so next-swc's gnu binary loads natively — no apk, no CDN.
 WORKDIR /app
 
 COPY package.json package-lock.json* ./
@@ -21,7 +20,7 @@ RUN for i in 1 2 3 4 5; do \
     echo "npm ci failed after 5 attempts" && exit 1
 
 # ── Stage 2: build ───────────────────────────────────────────────────────────
-FROM mirror.soroushasadi.com/node:20-alpine AS builder
+FROM mirror.soroushasadi.com/node:20-slim AS builder
 WORKDIR /app
 
 COPY --from=deps /app/node_modules ./node_modules
@@ -54,15 +53,15 @@ ENV NODE_ENV=production
 RUN npm run build
 
 # ── Stage 3: production runner ────────────────────────────────────────────────
-FROM mirror.soroushasadi.com/node:20-alpine AS runner
+FROM mirror.soroushasadi.com/node:20-slim AS runner
 WORKDIR /app
 
 ENV NODE_ENV=production
 ENV NEXT_TELEMETRY_DISABLED=1
 
-# Create a non-root user (security best practice)
-RUN addgroup --system --gid 1001 nodejs \
- && adduser  --system --uid 1001 nextjs
+# Create a non-root user (security best practice). Debian uses groupadd/useradd.
+RUN groupadd --system --gid 1001 nodejs \
+ && useradd  --system --uid 1001 --gid nodejs nextjs
 
 # Copy public assets
 COPY --from=builder /app/public ./public

docker-compose.v2.yml

@@ -370,7 +370,7 @@ services:
       gateway:
         condition: service_healthy
     healthcheck:
-      test: ["CMD-SHELL", "wget -qO- http://127.0.0.1:3000 || exit 1"]
+      test: ["CMD", "node", "-e", "require('http').get('http://127.0.0.1:3000',r=>process.exit(r.statusCode<500?0:1)).on('error',()=>process.exit(1))"]
       interval: 30s
       timeout: 10s
       retries: 3

scripts/seed_remotion_templates.py

@@ -67,6 +67,10 @@ TEXTCOLORS = {
     "AppShowcase3D": "#0f172a",
 }
 
+# Templates that ship a distinct preview video PER aspect (so the detail page shows
+# the matching render, not the 16:9 cropped). Others reuse the single 16:9 preview.
+PERASPECT_VIDEO = {"AppShowcase3D"}
+
 def swatch_svg(colors):
     rects = "".join(f'<rect x="{i*50}" y="0" width="50" height="40" fill="{c}"/>' for i, c in enumerate(colors))
     return f'<svg xmlns="http://www.w3.org/2000/svg" width="200" height="40">{rects}</svg>'
@@ -94,10 +98,11 @@ for idx, (tid, slug, name, desc, dur, texts, (accent, sec, bg)) in enumerate(T):
         pid = uid(f"p-{tid}-{asp}")
         sid = uid(f"s-{tid}-{asp}")
         thumb = f"{MINIO}/template-media/{tid}-{asp}.png"
+        pvideo = f"{MINIO}/template-media/{tid}-{asp}.mp4" if tid in PERASPECT_VIDEO else preview
         out.append(
             "INSERT INTO content.projects (id,container_id,name,image,full_demo,original_width,original_height,aspect,"
             "project_duration_sec,free_fps,choose_mode,resolution,render_engine,render_remotion_comp,is_published,sort) VALUES ("
-            f"{q(pid)},{q(cid)},{q(aspstr)},{q(thumb)},{q(preview)},{w},{h},{q(aspstr)},"
+            f"{q(pid)},{q(cid)},{q(aspstr)},{q(thumb)},{q(pvideo)},{w},{h},{q(aspstr)},"
             f"{dur},30,'FLEXIBLE','FullHD','Remotion',{q(tid+'-'+asp)},TRUE,0);")
         out.append(
             "INSERT INTO content.scenes (id,project_id,key,title,scene_color_svg,default_duration_sec,sort) VALUES ("

src/app/[locale]/templates/[id]/page.tsx

@@ -27,7 +27,7 @@ async function resolveTemplate(id: string): Promise<VideoCatalogTemplate | null>
     const base = adminProjectToCatalogTemplate(admin);
     const variants = (await fetchTemplateVariants(id))
       .filter((v) => SUPPORTED_ASPECTS.has(v.aspect as TemplateDetailAspectRatio))
-      .map((v) => ({ aspect: v.aspect as TemplateDetailAspectRatio, projectId: v.projectId }));
+      .map((v) => ({ aspect: v.aspect as TemplateDetailAspectRatio, projectId: v.projectId, image: v.image, previewVideo: v.previewVideo }));
     return { ...base, variants };
   }
   return VIDEO_TEMPLATES_CATALOG.find((item) => item.id === id) ?? null;

src/components/templates/TemplateDetailPreview.tsx

@@ -32,8 +32,10 @@ export function TemplateDetailPreview({
   onSelectAspect,
 }: TemplateDetailPreviewProps) {
   const aspectOptions = getTemplateDetailAspectRatios(template);
-  const posterSrc = template.coverImageUrl ?? getVideoTemplateImageSrc(template.id);
-  const videoSrc = template.previewVideoUrl ?? getTemplatePreviewVideoSrc(template.id);
+  // Use the render that matches the selected aspect (not the 16:9 cover cropped).
+  const variant = template.variants?.find((v) => v.aspect === selectedAspect);
+  const posterSrc = variant?.image ?? template.coverImageUrl ?? getVideoTemplateImageSrc(template.id);
+  const videoSrc = variant?.previewVideo ?? template.previewVideoUrl ?? getTemplatePreviewVideoSrc(template.id);
 
   return (
     <div>

src/lib/admin-api.ts

@@ -214,13 +214,18 @@ export async function fetchProject(slug: string): Promise<AdminProject | null> {
  *  studio copies. Returns [] when none / unreachable. */
 export async function fetchTemplateVariants(
   slug: string
-): Promise<Array<{ aspect: string; projectId: string }>> {
+): Promise<Array<{ aspect: string; projectId: string; image?: string; previewVideo?: string }>> {
   const c = await safeGet<{
-    projects?: Array<{ id?: string; aspect?: string; is_published?: boolean }>;
+    projects?: Array<{ id?: string; aspect?: string; is_published?: boolean; image?: string | null; full_demo?: string | null; demo?: string | null }>;
   }>(`/v1/templates/${encodeURIComponent(slug)}`);
   return (c?.projects ?? [])
     .filter((p) => p?.id && p?.is_published && p?.aspect)
-    .map((p) => ({ aspect: p.aspect as string, projectId: p.id as string }));
+    .map((p) => ({
+      aspect: p.aspect as string,
+      projectId: p.id as string,
+      image: p.image ?? undefined,
+      previewVideo: p.full_demo ?? p.demo ?? undefined,
+    }));
 }
 
 /** True when the gateway content endpoint is reachable. */

src/lib/video-templates-catalog.ts

@@ -63,6 +63,10 @@ export type TemplateDetailAspectRatio = "16:9" | "1:1" | "9:16";
 export interface TemplateVariant {
   aspect: TemplateDetailAspectRatio;
   projectId: string;
+  /** Per-aspect thumbnail + preview video so the detail page shows the render
+   *  that actually matches the selected aspect (not the 16:9 cover cropped). */
+  image?: string;
+  previewVideo?: string;
 }
 
 export const TEMPLATE_STYLE_COUNT = 4;