ci(auto-sync): fix downstream trigger by pinning repo and adding workflow to main

The 'Trigger downstream image build' step in auto-sync-upstream.yml was
failing with 404 because:

1. After 'git remote add upstream ...', gh CLI auto-detected the upstream
   remote as the canonical repository and hit
   router-for-me/CLIProxyAPI's API instead of this fork. Pin the target
   explicitly with --repo "${{ github.repository }}".

2. workflow_dispatch requires the workflow file to live on the default
   branch. ghcr-remote-fix.yml only existed on the remote-fix branch,
   so the API could never resolve it. Add a copy on main.

Author: conversun

.github/workflows/auto-sync-upstream.yml

@@ -109,7 +109,7 @@ jobs:
         if: steps.merge.outputs.clean == 'true' && steps.build.outputs.ok == 'true'
         env:
           GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-        run: gh workflow run ghcr-remote-fix.yml --ref "${TARGET_BRANCH}"
+        run: gh workflow run ghcr-remote-fix.yml --repo "${{ github.repository }}" --ref "${TARGET_BRANCH}"
 
       - name: Prepare PR branch (build failure case)
         if: steps.merge.outputs.clean == 'true' && steps.build.outputs.ok != 'true'

.github/workflows/ghcr-remote-fix.yml

@@ -0,0 +1,60 @@
+name: ghcr-remote-fix
+
+on:
+  workflow_dispatch:
+  push:
+    branches:
+      - remote-fix
+
+env:
+  IMAGE: ghcr.io/${{ github.repository_owner }}/cli-proxy-api-plus
+
+jobs:
+  build-and-push:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Refresh models catalog
+        run: |
+          git fetch --depth 1 https://github.com/router-for-me/models.git main
+          git show FETCH_HEAD:models.json > internal/registry/models/models.json
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Login to GHCR
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Lowercase image name
+        run: echo "IMAGE=$(echo '${{ env.IMAGE }}' | tr '[:upper:]' '[:lower:]')" >> $GITHUB_ENV
+
+      - name: Generate Build Metadata
+        run: |
+          echo "VERSION=remote-fix" >> $GITHUB_ENV
+          echo "COMMIT=$(git rev-parse --short HEAD)" >> $GITHUB_ENV
+          echo "BUILD_DATE=$(date -u +%Y-%m-%dT%H:%M:%SZ)" >> $GITHUB_ENV
+
+      - name: Build and push (amd64)
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          platforms: linux/amd64
+          push: true
+          build-args: |
+            VERSION=${{ env.VERSION }}
+            COMMIT=${{ env.COMMIT }}
+            BUILD_DATE=${{ env.BUILD_DATE }}
+          tags: |
+            ${{ env.IMAGE }}:remote-fix
+            ${{ env.IMAGE }}:remote-fix-${{ env.COMMIT }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max