Rename Hightower components to Trebuchet

- Rename npm packages: @shannon/api -> @trebuchet/api, @shannon/worker -> @trebuchet/worker, @keygraph/shannon -> @trebuchet/cli
- Update CLI references from shannon/keygraph to trebuchet/trebuchet
- Update Dockerfile and CLAUDE.md to reflect new package names
- Update TypeScript imports in API to use @trebuchet/worker

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/cli/src/env.ts

@@ -163,7 +163,7 @@ export function validateCredentials(): CredentialValidation {
   const hint =
     getMode() === 'local'
       ? `No credentials found. Set ANTHROPIC_API_KEY in .env or export it.`
-      : `Authentication not configured. Export variables or run 'npx @keygraph/shannon setup'.`;
+      : `Authentication not configured. Export variables or run 'npx @trebuchet/cli setup'.`;
   return {
     valid: false,
     mode: 'api-key',