Vetted, compilable Rust templates for common Omni Gateway Policy Development Kit (PDK) features — JWT validation/generation, OAuth2 introspection, header/body manipulation, body streaming, rate limiting, spike control, CORS, IP filtering, JSON/XML validators, HTTP outbound calls, gRPC, DataWeave evaluation, caching, distributed locks, worker variables, request data, control flow, contracts, data storage, timers, logging, metadata, policy violations, stop_iteration, outbound policies, and PDK unit testing. Use whenever the user asks "how do I X in PDK?", "show me a PDK template for Y", "PDK Rust snippet for Z", "JWT template", "rate limit template", "header manipulation example", "PDK gRPC", "PDK DataWeave", or any prompt mapping to one of the 30 template files under templates/. Read the matching file and adapt it into the user's `src/lib.rs` (and companion files for multi-file features). For project scaffolding, build, and publish lifecycle, defer to `develop-pdk-policy`.