feat: Add Infrahub Jinja2 transforms for VLANs, interfaces, and VXLAN (#20)

Add three GraphQL queries, Jinja2 templates, and integration tests for
generating YANG-style JSON configuration payloads from Infrahub intent data,
suitable for gNMI Set operations on Arista EOS devices.

Queries (transforms/queries/):
- vlan_intent.gql: Fetches VLANs for a device via VTEP mappings and SVI
  interfaces, including VNI associations.
- interface_intent.gql: Fetches all interface types (loopback, ethernet, vlan,
  lag) with IP addresses and type-specific attributes.
- vxlan_intent.gql: Fetches VTEP config, VLAN-to-VNI mappings, and VRF-to-VNI
  mappings (L3VNI) via VRF device assignments.

Templates (transforms/templates/):
- vlan_yang.j2: Merges VLANs from both VTEP and SVI sources, deduplicates by
  vlan_id, and emits a sorted JSON array.
- interface_yang.j2: Emits a JSON array of interfaces sorted by name, with a
  "type" discriminator field for each interface kind.
- vxlan_yang.j2: Emits a JSON object with vtep config, vlan_vni_mappings, and
  vrf_vni_mappings sections.

Integration tests (transforms/tests/):
- One test directory per transform with input.json (sample GraphQL response for
  leaf1), output.json (expected result), and test.yml config.
- Test data reflects the lab topology: leaf1 VTEP 10.0.255.11, VLAN 40 / VNI
  110040, MLAG VLANs 4090/4091, underlay Ethernet11/12.

.infrahub.yml updated with queries and jinja2_transforms sections.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

transforms/templates/interface_yang.j2

@@ -0,0 +1,101 @@
+{#
+  interface_yang.j2 — Produce a JSON array of interface configuration objects.
+
+  Input: GraphQL response from interface_intent query.
+  Returns all interface types (loopback, ethernet, vlan, lag) for the device,
+  each with a "type" discriminator and type-specific attributes.
+#}
+{%- set interfaces = [] -%}
+
+{#— Loopback interfaces —#}
+{%- for edge in data.InfraInterfaceLoopback.edges -%}
+  {%- set iface = edge.node -%}
+  {%- set ip_list = [] -%}
+  {%- for ip_edge in iface.ip_addresses.edges -%}
+    {%- set _ = ip_list.append(ip_edge.node.address.value) -%}
+  {%- endfor -%}
+  {%- set _ = interfaces.append({
+    "type": "loopback",
+    "name": iface.name.value,
+    "description": iface.description.value,
+    "enabled": iface.enabled.value,
+    "mtu": iface.mtu.value,
+    "ip_addresses": ip_list
+  }) -%}
+{%- endfor -%}
+
+{#— Ethernet interfaces —#}
+{%- for edge in data.InfraInterfaceEthernet.edges -%}
+  {%- set iface = edge.node -%}
+  {%- set ip_list = [] -%}
+  {%- for ip_edge in iface.ip_addresses.edges -%}
+    {%- set _ = ip_list.append(ip_edge.node.address.value) -%}
+  {%- endfor -%}
+  {%- set lag_name = null -%}
+  {%- if iface.lag and iface.lag.node -%}
+    {%- set lag_name = iface.lag.node.name.value -%}
+  {%- endif -%}
+  {%- set _ = interfaces.append({
+    "type": "ethernet",
+    "name": iface.name.value,
+    "description": iface.description.value,
+    "enabled": iface.enabled.value,
+    "mtu": iface.mtu.value,
+    "speed": iface.speed.value,
+    "mode": iface.mode.value,
+    "lag": lag_name,
+    "ip_addresses": ip_list
+  }) -%}
+{%- endfor -%}
+
+{#— VLAN SVI interfaces —#}
+{%- for edge in data.InfraInterfaceVlan.edges -%}
+  {%- set iface = edge.node -%}
+  {%- set ip_list = [] -%}
+  {%- for ip_edge in iface.ip_addresses.edges -%}
+    {%- set _ = ip_list.append(ip_edge.node.address.value) -%}
+  {%- endfor -%}
+  {%- set vlan_id = null -%}
+  {%- if iface.vlan and iface.vlan.node -%}
+    {%- set vlan_id = iface.vlan.node.vlan_id.value -%}
+  {%- endif -%}
+  {%- set _ = interfaces.append({
+    "type": "vlan",
+    "name": iface.name.value,
+    "description": iface.description.value,
+    "enabled": iface.enabled.value,
+    "mtu": iface.mtu.value,
+    "vlan_id": vlan_id,
+    "virtual_router_address": iface.virtual_router_address.value,
+    "autostate": iface.autostate.value,
+    "ip_addresses": ip_list
+  }) -%}
+{%- endfor -%}
+
+{#— LAG / Port-Channel interfaces —#}
+{%- for edge in data.InfraInterfaceLag.edges -%}
+  {%- set iface = edge.node -%}
+  {%- set ip_list = [] -%}
+  {%- for ip_edge in iface.ip_addresses.edges -%}
+    {%- set _ = ip_list.append(ip_edge.node.address.value) -%}
+  {%- endfor -%}
+  {%- set member_list = [] -%}
+  {%- for member_edge in iface.members.edges -%}
+    {%- set _ = member_list.append(member_edge.node.name.value) -%}
+  {%- endfor -%}
+  {%- set _ = interfaces.append({
+    "type": "lag",
+    "name": iface.name.value,
+    "description": iface.description.value,
+    "enabled": iface.enabled.value,
+    "mtu": iface.mtu.value,
+    "lacp_mode": iface.lacp_mode.value,
+    "mlag_id": iface.mlag_id.value,
+    "members": member_list,
+    "ip_addresses": ip_list
+  }) -%}
+{%- endfor -%}
+
+{#— Sort by name and emit JSON array —#}
+{%- set sorted_ifaces = interfaces | sort(attribute='name') -%}
+{{ sorted_ifaces | tojson(indent=2) }}