add 11 new sub-agent types, fix model routing, add models.json

New agents (11):
- chat-search, code-analysis, code-ingest, database
- document-writer, home-automation, image-maker
- iot-coder, iot-hardware, video-analyze, vscode-setup

Fixes:
- Remove broken :deepseek suffix from coder-basic, coder-pro,
  devops-basic, devops-pro (caused silent fallback to parent model)
- Add models.json with openRouterRouting for DeepSeek, Qwen,
  MiniMax, Moonshot AI provider cache targeting

Additions:
- headroom-bridge extension (compress_for_agent tool)
- models.json with provider routing config

Cleanup:
- Remove old pi-subagents extension (replaced by @tintinweb/pi-subagents)

models.json

@@ -0,0 +1,56 @@
+{
+  "providers": {
+    "openrouter": {
+      "modelOverrides": {
+        "deepseek/deepseek-chat": {
+          "compat": {
+            "openRouterRouting": {
+              "order": ["deepseek"],
+              "allow_fallbacks": false
+            }
+          }
+        },
+        "deepseek/deepseek-v4-pro": {
+          "compat": {
+            "openRouterRouting": {
+              "order": ["deepseek"],
+              "allow_fallbacks": false
+            }
+          }
+        },
+        "qwen/qwen-3-coder-next": {
+          "compat": {
+            "openRouterRouting": {
+              "order": ["qwen"],
+              "allow_fallbacks": false
+            }
+          }
+        },
+        "qwen/qwen-2.5-vl": {
+          "compat": {
+            "openRouterRouting": {
+              "order": ["qwen"],
+              "allow_fallbacks": false
+            }
+          }
+        },
+        "minimax/minimax-m3": {
+          "compat": {
+            "openRouterRouting": {
+              "order": ["minimax"],
+              "allow_fallbacks": false
+            }
+          }
+        },
+        "moonshotai/kimi-k2.6": {
+          "compat": {
+            "openRouterRouting": {
+              "order": ["moonshotai"],
+              "allow_fallbacks": false
+            }
+          }
+        }
+      }
+    }
+  }
+}