feat(agent): layered system prompt, environment facts and intent-routed skills

Co-Authored-By: Claude Opus 5.5 <[email protected]>

packages/agent/src/index.ts

@@ -51,6 +51,7 @@ export {
   type UpstreamLoginInteraction,
   type UpstreamSpec,
 } from "./pi/upstream.ts";
+export * from "./prompt/index.ts";
 export { isSensitiveKey, REDACTED, redactForModel, redactString, summarizeForLog } from "./redact.ts";
 export * from "./runtime/port.ts";
 export {
@@ -62,4 +63,4 @@ export {
   resolveAgentSettings,
   THINKING_LEVELS,
 } from "./settings.ts";
-export { buildSystemPrompt, interactionRules, REPORT_FORMAT, type SystemPromptInput } from "./system-prompt.ts";
+export { buildSystemPrompt, type SystemPromptInput } from "./system-prompt.ts";