feat: an ordered backlog

A Backlog tab lists the tickets still to start in the order the team will
take them; drag them, or use the arrows, to reorder. Moving a ticket only
rewrites that ticket's rank, read from the event store, and board columns
follow the same order.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/api/openapi.json

@@ -2188,6 +2188,15 @@
               "type": "string"
             }
           },
+          {
+            "name": "sort",
+            "required": false,
+            "in": "query",
+            "description": "RECENT (default): last updated first. RANK: backlog order.",
+            "schema": {
+              "$ref": "#/components/schemas/IssueSort"
+            }
+          },
           {
             "name": "search",
             "required": false,
@@ -3098,6 +3107,118 @@
         ]
       }
     },
+    "/api/issues/{issue}/rank": {
+      "put": {
+        "description": "Between the ticket that ends up above it and the one below (either may be left out for the top or the bottom). Board columns follow the same order.",
+        "operationId": "IssuesController_rank",
+        "parameters": [
+          {
+            "name": "issue",
+            "required": true,
+            "in": "path",
+            "description": "Ticket id or key",
+            "schema": {
+              "example": "WEB-12",
+              "type": "string"
+            }
+          }
+        ],
+        "requestBody": {
+          "required": true,
+          "content": {
+            "application/json": {
+              "schema": {
+                "$ref": "#/components/schemas/RankIssueDto"
+              }
+            }
+          }
+        },
+        "responses": {
+          "200": {
+            "description": "",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/CommandResultDto"
+                }
+              }
+            }
+          },
+          "400": {
+            "description": "Invalid input",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/ApiErrorDto"
+                }
+              }
+            }
+          },
+          "401": {
+            "description": "Missing or rejected Pireon token",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/ApiErrorDto"
+                }
+              }
+            }
+          },
+          "403": {
+            "description": "Not a member of the project (or not allowed)",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/ApiErrorDto"
+                }
+              }
+            }
+          },
+          "404": {
+            "description": "Not found",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/ApiErrorDto"
+                }
+              }
+            }
+          },
+          "409": {
+            "description": "Someone changed it at the same time: retry",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/ApiErrorDto"
+                }
+              }
+            }
+          },
+          "422": {
+            "description": "Business rule (e.g. a transition the workflow forbids)",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/ApiErrorDto"
+                }
+              }
+            }
+          }
+        },
+        "security": [
+          {
+            "pireon-oauth": []
+          },
+          {
+            "pireon": []
+          }
+        ],
+        "summary": "Move the ticket in the backlog",
+        "tags": [
+          "Issues"
+        ]
+      }
+    },
     "/api/issues/{issue}/checklist": {
       "post": {
         "operationId": "IssuesController_addChecklistItem",
@@ -6940,6 +7061,10 @@
               }
             ]
           },
+          "rank": {
+            "type": "string",
+            "description": "Place in the backlog and its board column (ascending, as text)"
+          },
           "checklist": {
             "type": "array",
             "items": {
@@ -6986,6 +7111,7 @@
           "attachments",
           "watchers",
           "parent",
+          "rank",
           "checklist",
           "commentCount",
           "createdAt",
@@ -7421,6 +7547,13 @@
           "total"
         ]
       },
+      "IssueSort": {
+        "type": "string",
+        "enum": [
+          "RECENT",
+          "RANK"
+        ]
+      },
       "CreateIssueDto": {
         "type": "object",
         "properties": {
@@ -7656,6 +7789,23 @@
           "parent"
         ]
       },
+      "RankIssueDto": {
+        "type": "object",
+        "properties": {
+          "above": {
+            "type": "string",
+            "nullable": true,
+            "example": "WEB-4",
+            "description": "The ticket that ends up right above (id or key; null: the top)"
+          },
+          "below": {
+            "type": "string",
+            "nullable": true,
+            "example": "WEB-9",
+            "description": "The ticket that ends up right below (id or key; null: the bottom)"
+          }
+        }
+      },
       "ChecklistItemBodyDto": {
         "type": "object",
         "properties": {