Reorganize GHCR workflows

This removes the manual build workflow, unifying it with the automatic
GHCR release workflow and ensuring Docker images are autobuilt.

.github/workflows/docker-manual.yml

@@ -1,34 +0,0 @@
-name: Push to GHCR (Manual)
-
-on:
-  workflow_dispatch:
-    inputs:
-      tag:
-        required: true
-        description: "Build specific tag"
-
-jobs:
-  docker:
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v2
-        with:
-          ref: ${{ github.event.inputs.tag }}
-      - name: Set up Buildx
-        uses: docker/setup-buildx-action@v1
-      - name: Login to registry
-        uses: docker/login-action@v1
-        with:
-          registry: ghcr.io
-          username: ${{ github.repository_owner }}
-          password: ${{ secrets.GITHUB_TOKEN }}
-      - name: Build & push
-        uses: docker/build-push-action@v2
-        with:
-          context: .
-          platforms: linux/amd64,linux/arm64
-          push: true
-          tags: |
-            ghcr.io/${{ github.repository }}:latest
-            ghcr.io/${{ github.repository }}:${{ github.event.inputs.tag }}

.github/workflows/docker.yml

@@ -1,16 +1,31 @@
 name: Push to GHCR
 
 on:
-  release:
-    types:
-      - created
+  push:
+    tags:
+      - '*'
+  workflow_dispatch:
+    inputs:
+      tag:
+        required: true
+        description: "Build specific tag"
 
 jobs:
   docker:
     runs-on: ubuntu-latest
     steps:
+      - name: Set tag name from manual dispatch
+        if: ${{ github.event_name == "workflow_dispatch" }}
+        run: |
+          echo "tag_name=${{ github.event.inputs.tag }}" >> $GITHUB_ENV
+      - name: Set tag name from Git
+        if: ${{ github.event_name == "push" }}
+        run: |
+          echo "tag_name=${{ github.ref_name }}" >> $GITHUB_ENV
       - name: Checkout
         uses: actions/checkout@v2
+        with:
+          ref: ${{ env.tag_name }}
       - name: Set up Buildx
         uses: docker/setup-buildx-action@v1
       - name: Login to registry
@@ -27,4 +42,4 @@ jobs:
           push: true
           tags: |
             ghcr.io/${{ github.repository }}:latest
-            ghcr.io/${{ github.repository }}:${{ github.event.release.tag_name }}
+            ghcr.io/${{ github.repository }}:${{ env.tag_name }}