Dockerfile: install tsx globally so it stops disappearing

`npm install --no-save tsx` in the runner stage was reporting success
but the tsx binary kept vanishing from node_modules/.bin after the
Next.js standalone node_modules reshuffled its tree. The seed then
failed with "sh: tsx: not found" even after a clean rebuild.

Install tsx globally instead (npm install -g tsx@4 → /usr/local/bin/tsx),
which is PATH-resolvable regardless of any local node_modules churn.

Other seed-adjacent deps stay local (prisma CLI, dotenv, adapter-pg,
bcryptjs) because the seed script explicitly imports them and wants
them resolved from the app's local node_modules.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Dockerfile

@@ -44,18 +44,26 @@ COPY --from=builder /app/src/generated ./src/generated
 
 # Install runtime deps needed for migrations + seed. The Next.js standalone
 # bundle covers the app itself, but the seed script (prisma/seed-dow.ts) is
-# a separate .ts file executed via tsx and needs its own module graph:
+# a separate .ts file executed via tsx.
+#
+# tsx is installed GLOBALLY (lives at /usr/local/bin/tsx, on PATH
+# unconditionally). Installing it locally via `npm install --no-save tsx`
+# doesn't work reliably here because Next.js's standalone node_modules
+# layout aggressively reshuffles its own tree — the tsx binary was
+# repeatedly going missing from node_modules/.bin after what npm reported
+# as a successful install. Global install sidesteps that entirely.
+#
+# Other deps are local (alongside the standalone tree):
 #   prisma      — the migrate-deploy CLI
 #   dotenv      — prisma.config.ts imports dotenv/config
-#   tsx         — runs the seed without an ahead-of-time compile
 #   @prisma/adapter-pg — the driver the seed instantiates directly
 #   bcryptjs    — the seed hashes the admin's temp password
-RUN npm install --no-save \
-    prisma@7.4.2 \
-    dotenv@17.3.1 \
-    tsx@4 \
-    @prisma/adapter-pg@7.4.2 \
-    bcryptjs@3
+RUN npm install -g tsx@4 && \
+    npm install --no-save \
+      prisma@7.4.2 \
+      dotenv@17.3.1 \
+      @prisma/adapter-pg@7.4.2 \
+      bcryptjs@3
 
 # Create uploads directories for media storage
 RUN mkdir -p /data/uploads && chown nextjs:nodejs /data/uploads