feat(agent): unify models and validate OpenCode providers

Generate chat, task and learning models from agent-models.json.
Use WaterNetwork fast/expert models with 272k context and validate
upstream names before readiness. Add an isolated model check command
with signal-safe cleanup and plugin, Skill and MCP management docs.

Verified in isolation: type checks, 26 focused tests and both model
catalog checks; no model inference requests.

.dockerignore

@@ -5,6 +5,7 @@ node_modules
 .env
 .env.*
 .local.env
+agent-models.local.json
 dist
 .vscode
 data