feat: add subnet edit functionality with internal subnet labeling in workload traffic insights

Add SubnetUpdate schema with optional fields for PATCH operations, implement update_subnet endpoint with validation and audit logging, add subnet_label_for_ip helper to match IPs against known subnets using longest prefix matching, update flow_endpoint_label to show "internal (CIDR)" for traffic within known subnets instead of "external", add DNS servers and DHCP toggle to subnet form UI, implement edit

backend/app/api/v1/router.py

@@ -67,6 +67,7 @@ from app.schemas.domain import (
     SetupStatus,
     SubnetCreate,
     SubnetRead,
+    SubnetUpdate,
     TenantCreate,
     TenantRead,
     UserCreate,
@@ -246,6 +247,31 @@ def flow_int(value: object, default: int = 0) -> int:
         return default
 
 
+def subnet_label_for_ip(subnets: list[Subnet], value: str) -> str | None:
+    try:
+        address = ip_address(value)
+    except ValueError:
+        return None
+    matches: list[tuple[int, Subnet]] = []
+    for subnet in subnets:
+        try:
+            network = ip_network(subnet.cidr, strict=False)
+        except ValueError:
+            continue
+        if address in network:
+            matches.append((network.prefixlen, subnet))
+    if not matches:
+        return None
+    _, subnet = sorted(matches, key=lambda item: item[0], reverse=True)[0]
+    return f"internal ({subnet.cidr})"
+
+
+def flow_endpoint_label(owner: Workload | None, subnets: list[Subnet], value: str) -> str:
+    if owner:
+        return owner.name
+    return subnet_label_for_ip(subnets, value) or "external"
+
+
 def proxmox_action(action: str) -> str:
     return {"allow": "ACCEPT", "deny": "DROP", "reject": "REJECT"}.get(action, "ACCEPT")
 
@@ -868,6 +894,7 @@ def workload_insights(workload_id: str, _: CurrentUser, db: Session = Depends(ge
         address.address: db.get(Workload, address.workload_id)
         for address in db.scalars(select(IpAddress).where(IpAddress.workload_id.is_not(None))).all()
     }
+    known_subnets = db.scalars(select(Subnet).order_by(Subnet.cidr)).all()
     traffic = []
     if workload_ips:
         flows = db.scalars(
@@ -881,8 +908,8 @@ def workload_insights(workload_id: str, _: CurrentUser, db: Session = Depends(ge
             destination_owner = ip_owners.get(flow.destination_ip)
             traffic.append(
                 {
-                    "source": source_owner.name if source_owner else "external",
-                    "destination": destination_owner.name if destination_owner else "external",
+                    "source": flow_endpoint_label(source_owner, known_subnets, flow.source_ip),
+                    "destination": flow_endpoint_label(destination_owner, known_subnets, flow.destination_ip),
                     "source_ip": flow.source_ip,
                     "destination_ip": flow.destination_ip,
                     "protocol": flow.protocol,
@@ -972,6 +999,41 @@ def create_subnet(payload: SubnetCreate, user: CurrentUser, db: Session = Depend
     return subnet
 
 
+@api_router.patch("/ipam/subnets/{subnet_id}", response_model=SubnetRead)
+def update_subnet(subnet_id: str, payload: SubnetUpdate, user: CurrentUser, db: Session = Depends(get_db)) -> Subnet:
+    subnet = db.get(Subnet, subnet_id)
+    if not subnet:
+        raise HTTPException(status_code=404, detail="Subnet not found")
+    changes = payload.model_dump(exclude_unset=True)
+    if "cidr" in changes and not changes["cidr"]:
+        raise HTTPException(status_code=400, detail="CIDR is required")
+    if "network_id" in changes and not changes["network_id"]:
+        raise HTTPException(status_code=400, detail="Network is required")
+    if "network_id" in changes and changes["network_id"] and not db.get(Network, changes["network_id"]):
+        raise HTTPException(status_code=404, detail="Network not found")
+    old_values = {
+        "network_id": subnet.network_id,
+        "cidr": subnet.cidr,
+        "gateway": subnet.gateway,
+        "dns": subnet.dns,
+        "dhcp_enabled": subnet.dhcp_enabled,
+    }
+    for key, value in changes.items():
+        setattr(subnet, key, value)
+    commit_or_400(db)
+    db.refresh(subnet)
+    write_audit(
+        db,
+        action="ipam.subnet.updated",
+        object_type="subnet",
+        object_id=subnet.id,
+        user_id=user.id,
+        old_values=old_values,
+        new_values=changes,
+    )
+    return subnet
+
+
 @api_router.get("/ipam/addresses", response_model=list[IpAddressRead])
 def ipam_addresses(_: CurrentUser, db: Session = Depends(get_db)) -> list[dict]:
     addresses = db.scalars(select(IpAddress).order_by(IpAddress.address)).all()