Initial public release — aci-sim v0.16.0

aci-sim is a stateful REST simulator of a 2-site Cisco ACI fabric
(per-site APIC + ND/NDO management planes) — for testing ACI automation
(Ansible cisco.aci / cisco.mso, aci-py, custom REST clients) and CI gates
without real hardware.

Highlights: APIC + NDO REST surface served from one in-memory MIT built
from a declarative topology.yaml; port mode + sandbox (real per-device IPs
on :443) run modes; LLDP/CDP neighbor visibility; NDO->APIC deploy mirror
(multi-site templates materialize onto the target sites' APIC stores);
real-APIC fvBD default attributes; file-backed state save/restore; an
`aci-sim` CLI (validate/show/graph/run/new/init/lldp); and an 888-test suite.

History squashed for the public release.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.github/workflows/ci.yml

@@ -0,0 +1,53 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  test:
+    name: test (${{ matrix.os }}, py${{ matrix.python-version }})
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, macos-latest]
+        python-version: ["3.11", "3.12"]
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      - name: Install dependencies
+        run: pip install -r requirements.txt
+
+      - name: Run test suite
+        run: pytest -q
+
+  lint:
+    name: ruff (non-blocking)
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+
+      - name: Install ruff
+        run: pip install ruff
+
+      # Non-blocking on purpose: the repo currently carries a pre-existing lint
+      # baseline of ~60 errors (mostly import-order/unused-import findings from
+      # incremental PR-by-PR development). Tighten this to a real gate (drop the
+      # `|| true` and/or add `--exit-non-zero-on-fix`) once that baseline is
+      # cleaned up — tracked as a follow-up, not a blocker for public release.
+      - name: ruff check (informational)
+        run: ruff check . || true