Implement local agent JWT authentication for adapters

Add HS256 JWT-based authentication for local adapters (claude_local, codex_local)
so agents authenticate automatically without manual API key configuration. The
server mints short-lived JWTs per heartbeat run and injects them as PAPERCLIP_API_KEY.
The auth middleware verifies JWTs alongside existing static API keys.

Includes: CLI onboard/doctor JWT secret management, env command for deployment,
config path resolution from ancestor directories, dotenv loading on server startup,
event payload secret redaction, multi-status issue filtering, and adapter transcript
parsing for thinking/user message kinds.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

cli/src/checks/index.ts

@@ -7,6 +7,7 @@ export interface CheckResult {
   repairHint?: string;
 }
 
+export { agentJwtSecretCheck } from "./agent-jwt-secret-check.js";
 export { configCheck } from "./config-check.js";
 export { databaseCheck } from "./database-check.js";
 export { llmCheck } from "./llm-check.js";