refactor(catalog)!: split model catalog from pi-ai

Move bundled models, model cache/manager, thinking metadata, effort helpers,
provider descriptors/discovery, wire constants, and model identity utilities
into the new @oh-my-pi/pi-catalog package.

Update pi-ai to keep provider runtime/auth concerns, move catalog provider
metadata into CATALOG_PROVIDERS, and migrate coding-agent, agent, stats, docs,
and tests to import catalog values from pi-catalog.

Split coding-agent model registry helpers into discovery, roles, and models
config modules while preserving registry orchestration.

BREAKING CHANGE: @oh-my-pi/pi-ai no longer exports catalog subpaths such as
/models, /model-cache, /model-manager, /model-thinking, /effort,
/provider-models*, discovery helpers, and provider wire constants; use the
matching @oh-my-pi/pi-catalog subpaths instead.

biome.json

@@ -62,7 +62,7 @@
 			"!**/test-sessions.ts",
 			"!**/template.generated.ts",
 			"!**/docs-index.generated.ts",
-			"!**/gen/agent_pb.ts",
+			"!**/agent_pb.ts",
 			"!.worktrees/**/*",
 			"!.wt/**/*"
 		]