Pull all fallback base images from Harbor, not Docker Hub

Every language's Dockerfile fallback template now pulls from
harbor.192.168.1.7.nip.io/base-images/... (mirrored from Docker Hub via
the new devops-base-images repo) instead of pulling live from Docker
Hub on every build. Eliminates that external dependency at build time,
and lets the mirrored tags be deliberately the leanest official
variant rather than whatever a public tag happens to default to.

- go: unchanged tags (golang:1.22-alpine, alpine:3.20 — already
  minimal), just re-hosted.
- node/python/java: moved from their Debian-slim defaults to the
  -alpine equivalent (node:20-alpine, python:3.12-alpine,
  maven:3-eclipse-temurin-21-alpine, eclipse-temurin:21-jre-alpine).
- php: bigger change — dropped php:*-apache (Debian, full Apache
  httpd) entirely for php:*-cli-alpine + PHP's own built-in dev server
  (`php -S`), moving to port 8080 like every other language instead of
  PHP's special-cased 80. Not production-grade PHP serving (PHP's own
  docs call the built-in server not designed for that), but genuinely
  minimal and fine for a homelab/demo app — would need php-fpm+nginx
  for anything serving real traffic.

Only versions actually mirrored into Harbor resolve now — a
dockerBuildVersion whose tag isn't in devops-base-images/images.txt
needs that added and re-mirrored first, unlike pulling straight from
Docker Hub where any tag "just worked". Chose keeping a shell (Alpine)
over full distroless — homelab kubectl-exec debuggability weighed more
than the last bit of attack-surface reduction.

resources/com/homelab/java-Dockerfile

@@ -1,15 +1,21 @@
 # Fallback only — see go-Dockerfile's header comment for the general
-# rule. Simplified from the real java-Dockerfile: no JFrog artifact
+# rule, including the Harbor base-images sourcing (also applies here).
+# Simplified from the real java-Dockerfile: no JFrog artifact
 # resolution, no Homelab-internal Maven mirror. Assumes a standard Maven
-# repo producing a single runnable jar under target/.
-FROM maven:3-eclipse-temurin-${version} AS build
+# repo producing a single runnable jar under target/. Switched both
+# stages from their Debian defaults to the -alpine variant — smaller,
+# still keeps a shell (not distroless). Maven itself still reaches out
+# to Maven Central for plugins/dependencies during the build regardless
+# of base image — this only removes the Docker Hub dependency for the
+# base image layer, not package-registry traffic during the build.
+FROM harbor.192.168.1.7.nip.io/base-images/maven:3-eclipse-temurin-${version}-alpine AS build
 WORKDIR /src
 COPY pom.xml .
 RUN mvn -B dependency:go-offline
 COPY . .
 RUN mvn -B package -DskipTests
 
-FROM eclipse-temurin:${version}-jre
+FROM harbor.192.168.1.7.nip.io/base-images/eclipse-temurin:${version}-jre-alpine
 WORKDIR /app
 COPY --from=build /src/target/*.jar app.jar
 EXPOSE 8080