ci: inline the two composite actions with one caller each

Both existed to give the matrix a per-target hook. folio-app and
headless-chrome stay: three and three callers.

Claude-Session: https://claude.ai/code/session_01ShuAy8q8ZfPi8KHxwc8JpQ

.github/actions/folio-simulator/action.yml

@@ -1,31 +0,0 @@
-name: folio on a simulator
-description: Boot an iOS simulator, install folio on it, and leave the app stopped.
-
-inputs:
-  device:
-    description: simulator device name
-    default: iPhone 16 Pro
-
-runs:
-  using: composite
-  steps:
-    - name: Boot a simulator
-      shell: bash
-      run: |
-        xcrun simctl boot "$IOS_DEVICE" || true
-        xcrun simctl bootstatus "$IOS_DEVICE" -b
-      env:
-        IOS_DEVICE: ${{ inputs.device }}
-
-    - name: Build and install folio
-      shell: bash
-      working-directory: examples/folio
-      run: just ios
-      env:
-        IOS_DEVICE: ${{ inputs.device }}
-
-    # `just ios` leaves the app running, and the run's first act is to clear
-    # its state. Stopping it here means the run always opens the same way.
-    - name: Stop the app before the run
-      shell: bash
-      run: xcrun simctl terminate booted app.folio || true

.github/actions/replay-ui-fixture/action.yml

@@ -1,55 +0,0 @@
-name: replay ui fixture
-description: Record a trace with sanderling, then serve it with sanderling replay.
-
-outputs:
-  url:
-    description: the step page of the served run, for a spec to drive
-    value: ${{ steps.serve.outputs.url }}
-
-runs:
-  using: composite
-  steps:
-    # A trace with a violation and uncaught exceptions in it, so the UI has
-    # something to render in every panel the spec looks at. No
-    # --exit-on-violation here: the run is the fixture, and stopping it at the
-    # first violation would leave a four-step trace to fuzz.
-    - name: Record a fixture trace
-      shell: bash
-      run: |
-        python3 -m http.server 8792 --bind 127.0.0.1 \
-          --directory test/browser/testdata/throwing &
-        ready=""
-        for _ in $(seq 1 30); do
-          curl -sf http://127.0.0.1:8792/ >/dev/null && { ready=1; break; }
-          sleep 1
-        done
-        if [ -z "$ready" ]; then
-          echo "the fixture http server never answered on 127.0.0.1:8792" >&2
-          exit 1
-        fi
-        ./bin/sanderling test \
-          --platform web \
-          --spec test/browser/testdata/throwing/spec.ts \
-          --bundle-id http://127.0.0.1:8792/ \
-          --duration 5m --max-steps 25 --seed 7 \
-          --output runs/fixture
-
-    - name: Serve the trace with sanderling replay
-      id: serve
-      shell: bash
-      run: |
-        # Flags before the positional argument: Go's flag package stops
-        # parsing at the first non-flag word.
-        ./bin/sanderling replay --port 8793 --no-open runs/fixture &
-        ready=""
-        for _ in $(seq 1 30); do
-          curl -sf http://127.0.0.1:8793/api/runs >/dev/null && { ready=1; break; }
-          sleep 1
-        done
-        if [ -z "$ready" ]; then
-          echo "sanderling replay never served /api/runs on 127.0.0.1:8793" >&2
-          exit 1
-        fi
-        run_id="$(ls runs/fixture | head -1)"
-        echo "url=http://127.0.0.1:8793/runs/$run_id/steps/1" >> "$GITHUB_OUTPUT"
-        curl -sf "http://127.0.0.1:8793/runs/$run_id/steps/1" >/dev/null