news-digest: multi-tenant deploy + masthead overlap fix

Two pieces:

1) Multi-tenant onboarding via scripts/add-digest-user.sh

   Shared miniflux + per-user digest stack. Onboarding a teammate
   takes one command (plus a one-time sudo for dir creation):

     scripts/add-digest-user.sh <username>

   What the script does:
     - Reads miniflux admin creds from ana-docker
     - Allocates next free port (scans existing digest-*/.env)
     - Generates a random password (or accepts one as 2nd arg)
     - Creates the miniflux user via the admin API
     - Materializes a per-user .env at /opt/docker/compose/digest-<user>/
       (inherits NEWS_DIGEST_TAG from the canonical stack so all
       tenants run the same image)
     - Brings up `docker compose -p digest-<user> up -d`
     - Seeds default world/local feeds in the new user's miniflux
     - Triggers a first digest run

   compose.yaml now uses ${DIGEST_PROJECT:-news-digest} to namespace
   container_name + homepage labels. Default keeps backward-compat
   for the singleton install — existing stacks unaffected.

2) Masthead overlap on phone widths

   Desktop CSS pinned .masthead-edition to grid-row 1, which collided
   with .masthead-brand once the mobile media query collapsed both
   to grid-column 1. Result: "MORNING EDITION" badge stacked on top
   of the "DAILY DIGEST" hero. Reset grid-row to `auto` for all
   three masthead children in the ≤720 px breakpoint so they
   auto-flow vertically.

stacks/news-digest/compose.yaml

@@ -21,7 +21,11 @@ services:
     build:
       context: .
       dockerfile: Dockerfile
-    container_name: news-digest-worker
+    # ${DIGEST_PROJECT} prefixes container names so multiple instances
+    # (one per teammate, scoped to their miniflux user) can coexist on
+    # the same host. Default keeps backward-compat with the original
+    # singleton deploy.
+    container_name: ${DIGEST_PROJECT:-news-digest}-worker
     restart: unless-stopped
     environment:
       - TZ=${NEWS_DIGEST_TZ:-America/Los_Angeles}
@@ -57,7 +61,7 @@ services:
     build:
       context: .
       dockerfile: Dockerfile
-    container_name: news-digest-web
+    container_name: ${DIGEST_PROJECT:-news-digest}-web
     restart: unless-stopped
     depends_on:
       - news-digest-worker
@@ -90,9 +94,9 @@ services:
       - tnet
     labels:
       - homepage.group=News
-      - homepage.name=Daily Digest
+      - homepage.name=${DIGEST_HOMEPAGE_NAME:-Daily Digest}
       - homepage.icon=mdi-newspaper-variant-outline
-      - homepage.description=LLM-curated briefing across feeds, twice daily
+      - homepage.description=${DIGEST_HOMEPAGE_DESC:-LLM-curated briefing across feeds, twice daily}
       - homepage.href=http://10.250.50.70:${NEWS_DIGEST_PORT}
 
 networks: