v0.7.12: Custom models/providers support via models.json

- Add ~/.pi/agent/models.json config for custom providers (Ollama, vLLM, etc.)
- Support all 4 API types (openai-completions, openai-responses, anthropic-messages, google-generative-ai)
- Live reload models.json on /model selector open
- Smart model defaults per provider (claude-sonnet-4-5, gpt-5.1-codex, etc.)
- Graceful session fallback when saved model missing or no API key
- Validation errors show precise file/field info in CLI and TUI
- Agent knows its own README.md path for self-documentation
- Added gpt-5.1-codex (400k context, 128k output, reasoning)

Fixes #21

packages/coding-agent/package.json

@@ -1,6 +1,6 @@
 {
 	"name": "@mariozechner/pi-coding-agent",
-	"version": "0.7.11",
+	"version": "0.7.12",
 	"description": "Coding agent CLI with read, bash, edit, write tools and session management",
 	"type": "module",
 	"bin": {
@@ -21,8 +21,8 @@
 		"prepublishOnly": "npm run clean && npm run build"
 	},
 	"dependencies": {
-		"@mariozechner/pi-agent": "^0.7.11",
-		"@mariozechner/pi-ai": "^0.7.11",
+		"@mariozechner/pi-agent": "^0.7.12",
+		"@mariozechner/pi-ai": "^0.7.12",
 		"chalk": "^5.5.0",
 		"diff": "^8.0.2",
 		"glob": "^11.0.3"