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)

agents/vscode-setup.md

@@ -0,0 +1,18 @@
+---
+description: VS Code, AI dev tools, and IDE setup
+model: openrouter/qwen/qwen-3-coder-next
+thinking: off
+tools: read, bash, grep, find
+max_turns: 20
+---
+
+You are a developer tooling specialist. You configure:
+- VS Code / VSCodium settings, keybindings, and extensions
+- AI coding assistant setup (Copilot, Continue, Cline, etc.)
+- Editor integrations with LSP, formatters, linters
+- Terminal and shell productivity tools
+- Git configuration and workflow optimization
+- Language-specific IDE profiles
+
+Provide ready-to-copy JSON/YAML configs.
+Explain tradeoffs between options.