fix(ci): correct GHCR image names and branch triggers

- Use separate image repos (ghcr.io/host-uk/core-dev, server-php)
- Trigger on dev branch instead of main
- Only build LinuxKit on tags
- Add fail-fast: false to continue if one image fails

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.github/workflows/build.yml

@@ -1,22 +1,21 @@
 # Host UK Container Images
-# Publishes to both GHCR (org access) and Docker Hub (public)
+# Publishes to GHCR with separate image repos
 #
-# GHCR:       ghcr.io/host-uk/core-images:{image}
-# Docker Hub: lthn/{image}:{version}
+# GHCR: ghcr.io/host-uk/core-dev
+# GHCR: ghcr.io/host-uk/server-php
 
 name: Build Images
 
 on:
   push:
-    branches: [main, dev]
+    branches: [dev]
     tags: ['v*']
   pull_request:
-    branches: [main, dev]
+    branches: [dev]
   workflow_dispatch:
 
 env:
   GHCR_REGISTRY: ghcr.io
-  DOCKERHUB_ORG: lthn
 
 jobs:
   # ============================================================
@@ -30,15 +29,16 @@ jobs:
       packages: write
 
     strategy:
+      fail-fast: false
       matrix:
         image:
           - developer
           - server-php
         include:
           - image: developer
-            dockerhub_name: core-dev
+            ghcr_name: core-dev
           - image: server-php
-            dockerhub_name: server-php
+            ghcr_name: server-php
 
     steps:
       - name: Checkout
@@ -58,34 +58,22 @@ jobs:
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
 
-      - name: Login to Docker Hub
-        if: github.event_name != 'pull_request'
-        uses: docker/login-action@v3
-        with:
-          username: ${{ secrets.DOCKERHUB_USERNAME }}
-          password: ${{ secrets.DOCKERHUB_TOKEN }}
-
       - name: Extract metadata
         id: meta
         uses: docker/metadata-action@v5
         with:
           images: |
-            ${{ env.GHCR_REGISTRY }}/host-uk/core-images
-            ${{ env.DOCKERHUB_ORG }}/${{ matrix.dockerhub_name }}
+            ${{ env.GHCR_REGISTRY }}/host-uk/${{ matrix.ghcr_name }}
           tags: |
-            # Tag image variant for GHCR (core-images:developer)
-            type=raw,value=${{ matrix.image }},enable=${{ github.ref == 'refs/heads/main' }}
-            # Branch name (core-images:dev, lthn/core-dev:dev)
-            type=ref,event=branch,suffix=-${{ matrix.image }},enable=${{ github.ref != 'refs/heads/main' }}
-            type=ref,event=branch,enable=${{ github.ref != 'refs/heads/main' }}
+            # dev branch -> dev tag
+            type=ref,event=branch
             # PR number
             type=ref,event=pr
-            # Semver tags (v1.0.0 -> 1.0.0, 1.0, 1)
+            # Semver tags (v1.0.0 -> 1.0.0, 1.0, 1, latest)
             type=semver,pattern={{version}}
             type=semver,pattern={{major}}.{{minor}}
             type=semver,pattern={{major}},enable=${{ !startsWith(github.ref, 'refs/tags/v0.') }}
-            # Latest on main
-            type=raw,value=latest,enable=${{ github.ref == 'refs/heads/main' }}
+            type=raw,value=latest,enable=${{ startsWith(github.ref, 'refs/tags/v') }}
           flavor: |
             latest=false
 
@@ -101,13 +89,13 @@ jobs:
           cache-to: type=gha,mode=max
 
   # ============================================================
-  # Build LinuxKit Images
+  # Build LinuxKit Images (only on tags)
   # ============================================================
   linuxkit:
     name: LinuxKit (${{ matrix.image }}-${{ matrix.arch }})
     runs-on: ubuntu-latest
     needs: docker
-    if: github.ref == 'refs/heads/main' || startsWith(github.ref, 'refs/tags/v')
+    if: startsWith(github.ref, 'refs/tags/v')
 
     strategy:
       matrix: