test: add templates API E2E test for shared-variables project

Adds test/templates/api/projects/project-with-shared-variables/ which
sets up a project where a keboola.variables config is referenced by two
consumer configs (identical to the CLI variables-used-twice fixture) and
calls GET /v1/project/{branch}/instances.

That endpoint calls prj.LoadState with LoadRemoteState:true, triggering
AfterRemoteOperation and the full mapper chain. Without the two-pass fix
this returned 500 "multiple parents defined by relations"; with the fix
it returns 200 with an empty instances list.

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

Author: Matovidlo

test/templates/api/projects/project-with-shared-variables/001-list-instances/expected-http-code

@@ -0,0 +1 @@
+200

test/templates/api/projects/project-with-shared-variables/001-list-instances/expected-response.json

@@ -0,0 +1,3 @@
+{
+  "instances": []
+}

test/templates/api/projects/project-with-shared-variables/001-list-instances/request.json

@@ -0,0 +1,9 @@
+{
+  "path": "/v1/project/%%TEST_BRANCH_MAIN_ID%%/instances",
+  "method": "GET",
+  "headers": {
+    "Content-Type": "application/json",
+    "X-StorageApi-Token": "%%TEST_KBC_STORAGE_API_TOKEN%%"
+  },
+  "body": {}
+}

test/templates/api/projects/project-with-shared-variables/expected-state.json

@@ -0,0 +1,64 @@
+{
+  "branches": [
+    {
+      "branch": {
+        "name": "Main",
+        "description": "",
+        "isDefault": true
+      },
+      "configs": [
+        {
+          "componentId": "ex-generic-v2",
+          "name": "With Variables 1",
+          "description": "",
+          "configuration": {
+            "variables_id": "%s",
+            "variables_values_id": "%s"
+          },
+          "rows": [],
+          "isDisabled": false
+        },
+        {
+          "componentId": "ex-generic-v2",
+          "name": "With Variables 2",
+          "description": "",
+          "configuration": {
+            "variables_id": "%s",
+            "variables_values_id": "%s"
+          },
+          "rows": [],
+          "isDisabled": false
+        },
+        {
+          "componentId": "keboola.variables",
+          "name": "Variables",
+          "description": "",
+          "configuration": {
+            "variables": [
+              {
+                "name": "foo",
+                "type": "string"
+              }
+            ]
+          },
+          "rows": [
+            {
+              "name": "Default values",
+              "description": "",
+              "isDisabled": false,
+              "configuration": {
+                "values": [
+                  {
+                    "name": "foo",
+                    "value": "bar"
+                  }
+                ]
+              }
+            }
+          ],
+          "isDisabled": false
+        }
+      ]
+    }
+  ]
+}

test/templates/api/projects/project-with-shared-variables/initial-state.json

@@ -0,0 +1,25 @@
+{
+  "backend": {
+    "type": "snowflake"
+  },
+  "allBranchesConfigs": [],
+  "branches": [
+    {
+      "branch": {
+        "name": "Main",
+        "isDefault": true
+      },
+      "configs": [
+        "with-variables-1",
+        "with-variables-2",
+        "variables"
+      ]
+    }
+  ],
+  "envs": {
+    "TEST_CONFIG_WITH_VARIABLES_1_VARIABLES_ID": "%%TEST_BRANCH_MAIN_CONFIG_VARIABLES_ID%%",
+    "TEST_CONFIG_WITH_VARIABLES_1_VARIABLES_VALUES_ID": "%%TEST_BRANCH_MAIN_CONFIG_VARIABLES_ROW_DEFAULT_VALUES_ID%%",
+    "TEST_CONFIG_WITH_VARIABLES_2_VARIABLES_ID": "%%TEST_BRANCH_MAIN_CONFIG_VARIABLES_ID%%",
+    "TEST_CONFIG_WITH_VARIABLES_2_VARIABLES_VALUES_ID": "%%TEST_BRANCH_MAIN_CONFIG_VARIABLES_ROW_DEFAULT_VALUES_ID%%"
+  }
+}