ci: remove GitHub CI — native git.hanzo.ai + cd.hanzo.ai only

This workflow ran on a self-hosted actions-runner-controller pool. ARC is
decommissioned: CI executes inside git.hanzo.ai (Gitea Actions, .hanzo/workflows)
and delivery is cd.hanzo.ai reconciling the reviewed image pin in
hanzoai/universe. GitHub is a mirror and runs nothing.

Removed rather than repointed — there is no GitHub-side pool to move to, and
leaving it would keep ARC load-bearing.

.github/workflows/deploy-ui-embed.yml

@@ -1,63 +0,0 @@
-name: Deploy UI embed image
-
-# Builds the monochrome ArgoCD UI bundle as ghcr.io/hanzoai/deploy-ui-embed on
-# Hanzo runners — the go:embed source hanzoai/cloud consumes for /v1/deploy/ui.
-# Mirrors console-embed (hanzoai/console build-image.yml). Runs on the
-# rebrand/hanzo-monochrome lineage, where the monochrome UI lives.
-
-on:
-  push:
-    branches: ['rebrand/hanzo-monochrome']
-    paths: ['ui/**', 'Dockerfile.embed', '.github/workflows/deploy-ui-embed.yml']
-  workflow_dispatch:
-
-permissions:
-  contents: read
-  packages: write
-
-jobs:
-  embed:
-    runs-on: hanzo-build-linux-amd64
-    permissions:
-      contents: read
-      packages: write
-    steps:
-      - uses: actions/checkout@v4
-
-      - uses: docker/setup-buildx-action@v3
-
-      - name: Reset Docker credential store (runner hygiene)
-        run: |
-          mkdir -p "$HOME/.docker"
-          printf '{}' > "$HOME/.docker/config.json"
-
-      - name: Log in to ghcr.io
-        uses: docker/login-action@v3
-        with:
-          registry: ghcr.io
-          username: ${{ github.actor }}
-          password: ${{ secrets.GH_PAT || secrets.GITHUB_TOKEN }}
-
-      - name: Metadata
-        id: meta
-        uses: docker/metadata-action@v5
-        with:
-          images: ghcr.io/hanzoai/deploy-ui-embed
-          # `latest` so cloud's Dockerfile ARG default resolves; sha-<short> for
-          # pinning a cloud release to an exact UI bundle.
-          tags: |
-            type=raw,value=latest
-            type=sha,prefix=sha-,format=short
-
-      - name: Build and push
-        uses: docker/build-push-action@v6
-        with:
-          context: .
-          file: ./Dockerfile.embed
-          platforms: linux/amd64
-          tags: ${{ steps.meta.outputs.tags }}
-          labels: ${{ steps.meta.outputs.labels }}
-          push: ${{ github.event_name != 'pull_request' }}
-          provenance: false
-          cache-from: type=gha,scope=deploy-ui-embed-amd64
-          cache-to: type=gha,scope=deploy-ui-embed-amd64,mode=max