Research efforts can be ideas, and at most three are active (issue 1970, ADR 0629)

The roadmap lives in the knowledge base: an idea is listed, never served as in force; propose refuses a further active effort.

Claude-Session: https://claude.ai/code/session_01JG73KG7AfSdh6FP8VrBqCn

modules/mesh-knowledge/module.json

@@ -111,6 +111,12 @@
       "description": "How long a reserved number waits for its proposal before it is withdrawn, as a duration such as 168h; empty is the knowledge base's own default.",
       "pattern": "|[0-9]+(\\.[0-9]+)?(ns|us|µs|ms|s|m|h)([0-9]+(\\.[0-9]+)?(ns|us|µs|ms|s|m|h))*",
       "default": "168h"
+    },
+    "research-active-at-most": {
+      "type": "number",
+      "description": "The most research efforts that may be active at once; propose refuses a further one, which is parked as an idea instead. 0 or empty is 3.",
+      "minimum": 0,
+      "default": 3
     }
   },
   "resources": [
@@ -134,7 +140,7 @@
       "type": "file",
       "path": "${dir:state}/settings.json",
       "mode": "0600",
-      "takes-config": ["judge-model", "drafting", "reserved-for"],
+      "takes-config": ["judge-model", "drafting", "reserved-for", "research-active-at-most"],
       "merge": "json",
       "template": "files/settings.json"
     },