Add direct diagram connections, movable ports, and contextual authoring

docs/openapi.json

@@ -3615,6 +3615,32 @@
         ],
         "additionalProperties": false
       },
+      "PortAnchorSide": {
+        "type": "string",
+        "enum": ["Left", "Right", "Top", "Bottom"],
+        "description": "Presentation side of the owner placement; independent of semantic port direction."
+      },
+      "PortAnchor": {
+        "type": "object",
+        "description": "Manual position of a direct child Port on one owner placement. Each port occurs at most once per placement; this record has no separate identity.",
+        "properties": {
+          "port": {
+            "type": "string",
+            "format": "uuid"
+          },
+          "side": {
+            "$ref": "#/components/schemas/PortAnchorSide"
+          },
+          "offset": {
+            "type": "number",
+            "minimum": 0,
+            "maximum": 1,
+            "description": "Finite binary32 fraction of the complete owner edge, measured from top on Left/Right and from left on Top/Bottom."
+          }
+        },
+        "required": ["port", "side", "offset"],
+        "additionalProperties": false
+      },
       "NodePlacement": {
         "type": "object",
         "properties": {
@@ -3639,6 +3665,14 @@
           },
           "collapsed": {
             "type": "boolean"
+          },
+          "port_anchors": {
+            "type": "array",
+            "items": {
+              "$ref": "#/components/schemas/PortAnchor"
+            },
+            "default": [],
+            "description": "Per-placement manual port positions. Omitted and empty both select automatic positioning; empty lists are omitted on serialization. Duplicate port references are invalid."
           }
         },
         "required": [
@@ -4734,6 +4768,42 @@
             ],
             "additionalProperties": false
           },
+          {
+            "type": "object",
+            "properties": {
+              "SetPortAnchor": {
+                "type": "object",
+                "description": "Upsert manual port position by port identity on an existing owner placement, preserving unrelated entries. Port must be a direct child of the placement's semantic element.",
+                "properties": {
+                  "diagram": { "type": "string", "format": "uuid" },
+                  "node": { "type": "string", "format": "uuid" },
+                  "anchor": { "$ref": "#/components/schemas/PortAnchor" }
+                },
+                "required": ["diagram", "node", "anchor"],
+                "additionalProperties": false
+              }
+            },
+            "required": ["SetPortAnchor"],
+            "additionalProperties": false
+          },
+          {
+            "type": "object",
+            "properties": {
+              "RemovePortAnchor": {
+                "type": "object",
+                "description": "Restore automatic positioning for an existing direct child Port. No-op when that valid owner placement has no manual anchor for the port; wrong or stale ownership is rejected.",
+                "properties": {
+                  "diagram": { "type": "string", "format": "uuid" },
+                  "node": { "type": "string", "format": "uuid" },
+                  "port": { "type": "string", "format": "uuid" }
+                },
+                "required": ["diagram", "node", "port"],
+                "additionalProperties": false
+              }
+            },
+            "required": ["RemovePortAnchor"],
+            "additionalProperties": false
+          },
           {
             "type": "object",
             "properties": {