feat: work-in-progress limits and swimlanes on the board

Each status can carry a WIP limit in the project settings; the board shows
it next to the count, marks a column that goes over it and says so when a
card is dropped there. The board can also be grouped in rows by person,
epic, priority or type, remembered per browser.

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

apps/api/openapi.json

@@ -7754,6 +7754,11 @@
           "archived": {
             "type": "boolean",
             "description": "No new tickets or transitions into it"
+          },
+          "wipLimit": {
+            "type": "number",
+            "nullable": true,
+            "description": "Work-in-progress limit (a warning, not a lock)"
           }
         },
         "required": [
@@ -7762,7 +7767,8 @@
           "category",
           "color",
           "requiresReason",
-          "archived"
+          "archived",
+          "wipLimit"
         ]
       },
       "StatusTransitionsDto": {
@@ -8067,6 +8073,13 @@
           "archived": {
             "type": "boolean",
             "default": false
+          },
+          "wipLimit": {
+            "type": "number",
+            "nullable": true,
+            "minimum": 1,
+            "maximum": 999,
+            "description": "Work-in-progress limit (null: none)"
           }
         },
         "required": [