feat: JWT token generation API + auto-inject TORI_JWT in executor

- POST /tori/api/token — sign ES256 JWT with configurable private key
- exec.rs auto-generates and injects TORI_JWT env var for all commands
- Config: jwt_private_key field for PEM file path

Dockerfile

@@ -22,6 +22,7 @@ COPY --from=frontend /app/web/dist ./web/dist/
 COPY scripts/embed.py ./scripts/
 COPY app-templates/ ./templates/
 COPY config.yaml .
+COPY data/jwt-private.pem ./data/
 
 EXPOSE 3000
 CMD ["./tori"]