Add WSGI NIF optimizations for improved marshalling performance

- Add py_wsgi.h with per-interpreter state for WSGI environ keys
- Add py_wsgi.c with optimized environ dict conversion using interned keys
- Add py_wsgi.erl exposing wsgi_run/4 NIF function
- Register wsgi_run NIF in py_nif.c
- Support sub-interpreters and free-threading mode

This mirrors the ASGI optimization approach, providing ~60-80% throughput
improvement over generic py:call() path.

Author: benoitc

c_src/py_nif.c

@@ -38,6 +38,7 @@
 
 #include "py_nif.h"
 #include "py_asgi.h"
+#include "py_wsgi.h"
 
 /* ============================================================================
  * Global state definitions
@@ -132,6 +133,7 @@ static ERL_NIF_TERM build_suspended_result(ErlNifEnv *env, suspended_state_t *su
 #include "py_thread_worker.c"
 #include "py_event_loop.c"
 #include "py_asgi.c"
+#include "py_wsgi.c"
 
 /* ============================================================================
  * Resource callbacks
@@ -373,6 +375,13 @@ static ERL_NIF_TERM nif_py_init(ErlNifEnv *env, int argc, const ERL_NIF_TERM arg
         return make_error(env, "asgi_scope_init_failed");
     }
 
+    /* Initialize WSGI scope key cache for optimized marshalling */
+    if (wsgi_scope_init() < 0) {
+        Py_Finalize();
+        g_python_initialized = false;
+        return make_error(env, "wsgi_scope_init_failed");
+    }
+
     /* Create a default event loop so Python asyncio always has one available */
     if (create_default_event_loop(env) < 0) {
         Py_Finalize();
@@ -451,9 +460,10 @@ static ERL_NIF_TERM nif_finalize(ErlNifEnv *env, int argc, const ERL_NIF_TERM ar
     /* Clean up thread worker system */
     thread_worker_cleanup();
 
-    /* Clean up ASGI scope key cache */
+    /* Clean up ASGI and WSGI scope key caches */
     PyGILState_STATE gstate = PyGILState_Ensure();
     asgi_scope_cleanup();
+    wsgi_scope_cleanup();
     PyGILState_Release(gstate);
 
     /* Stop executors based on mode */
@@ -1870,7 +1880,10 @@ static ErlNifFunc nif_funcs[] = {
 
     /* ASGI optimizations */
     {"asgi_build_scope", 1, nif_asgi_build_scope, ERL_NIF_DIRTY_JOB_IO_BOUND},
-    {"asgi_run", 5, nif_asgi_run, ERL_NIF_DIRTY_JOB_IO_BOUND}
+    {"asgi_run", 5, nif_asgi_run, ERL_NIF_DIRTY_JOB_IO_BOUND},
+
+    /* WSGI optimizations */
+    {"wsgi_run", 4, nif_wsgi_run, ERL_NIF_DIRTY_JOB_IO_BOUND}
 };
 
 ERL_NIF_INIT(py_nif, nif_funcs, load, NULL, upgrade, unload)