W7f: sweep dead/legacy/fallback leftovers after native-pipeline removal

Post-deletion cleanup (units run only on wasm):
- types.h/compiler.cpp: drop the native-era SharedUnit fields so_name,
  bin_file_name, and the opt_so_optional cache-mode plumbing (no native
  optional .so path remains). The per-unit compile lock is re-keyed from
  so_name+.lock to wasm_name+.lock (still per-unit).
- unit_info() and to_string(SharedUnit*) no longer expose .so artifact fields.
- backend.h: drop the stale "+ fallback-token gate" comment.
- Docs/comments corrected to wasm-only reality: README, tests/README,
  site/doc C++ preprocessor + error_pages + unit_info pages, site/info intro,
  site/demo/unit-browser artifact card; the Phase-5 native-vs-wasm benchmark
  harness (tests/wasm_benchmark.py) reframed for the wasm-only backend.

Audit confirmed no live references remain to so_handle, load_shared_unit,
compiler_load_shared_unit, compiler_invoke*/_cli/_websocket/_serve_http,
COMPILE_SCRIPT/COMPILE_WASM_UNITS, or the native export-symbol constants;
request_ref_handler/dv_call_handler are kept (live wasm funcref casts).

Swept via the pi agent (delegated to a gpt-5.3-codex-spark sub-model);
independently re-verified on the host: run_cli_tests --include-wasm-kill =>
87 passed, 0 failed, 0 skipped.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/wasm/backend.h

@@ -6,8 +6,8 @@
 // backend.cpp — so it does not have to compile worker.cpp + wasmtime.hh on
 // every build. Include only after uce_lib.h (needs Request / String).
 
-// True if this request should be served by the wasm backend (config + artifact
-// + fallback-token gate); handler-agnostic, the caller names the handler.
+// True if this request can be served by the wasm backend for the named unit
+// artifact; handler-agnostic, the caller names the handler.
 bool wasm_backend_should_handle(Request& request, const String& entry_unit);
 
 // Serve a request through a wasm workspace by invoking a named unit handler —

src/wasm/core.cpp

@@ -564,7 +564,7 @@ static void wasm_run_once(const String& resolved, Request& request)
 		return;
 	String previous_unit = request.resources.current_unit_file;
 	request.resources.current_unit_file = resolved;
-	request_ref_handler once_handler = (request_ref_handler)(uintptr_t)once_slot;
+	WasmRequestHandler once_handler = (WasmRequestHandler)(uintptr_t)once_slot;
 	once_handler(request);
 	request.resources.current_unit_file = previous_unit;
 }
@@ -597,7 +597,7 @@ DValue* unit_call(String file_name, String function_name, DValue* call_param)
 		String previous_unit = context->resources.current_unit_file;
 		if(resolved != "")
 			context->resources.current_unit_file = resolved;
-		request_ref_handler handler_fn = (request_ref_handler)(uintptr_t)slot;
+		WasmRequestHandler handler_fn = (WasmRequestHandler)(uintptr_t)slot;
 		handler_fn(*context);
 		context->resources.current_unit_file = previous_unit;
 		return(0);
@@ -614,7 +614,7 @@ DValue* unit_call(String file_name, String function_name, DValue* call_param)
 	String previous_unit = context->resources.current_unit_file;
 	if(resolved != "")
 		context->resources.current_unit_file = resolved;
-	dv_call_handler handler_fn = (dv_call_handler)(uintptr_t)slot;
+	WasmDValueCallHandler handler_fn = (WasmDValueCallHandler)(uintptr_t)slot;
 	DValue* result = handler_fn(call_param);
 	context->resources.current_unit_file = previous_unit;
 	if(result)
@@ -644,7 +644,7 @@ void component_render(String name, DValue props, Request& request)
 		request.resources.current_unit_file = resolved;
 	// a wasm function pointer is its index in the shared funcref table; the
 	// host returned the handler's slot, so this is a plain call_indirect
-	request_ref_handler handler_fn = (request_ref_handler)(uintptr_t)slot;
+	WasmRequestHandler handler_fn = (WasmRequestHandler)(uintptr_t)slot;
 	handler_fn(request);
 	request.resources.current_unit_file = previous_unit;
 }
@@ -680,7 +680,7 @@ void unit_render(String file_name, Request& request)
 	String previous_unit = request.resources.current_unit_file;
 	if(resolved != "")
 		request.resources.current_unit_file = resolved;
-	request_ref_handler handler_fn = (request_ref_handler)(uintptr_t)slot;
+	WasmRequestHandler handler_fn = (WasmRequestHandler)(uintptr_t)slot;
 	handler_fn(request);
 	request.resources.current_unit_file = previous_unit;
 }
@@ -706,7 +706,7 @@ void uce_wasm_invoke_entry(const char* path, size_t path_len, const char* handle
 	String previous_unit = context->resources.current_unit_file;
 	if(resolved != "")
 		context->resources.current_unit_file = resolved;
-	request_ref_handler handler_fn = (request_ref_handler)(uintptr_t)slot;
+	WasmRequestHandler handler_fn = (WasmRequestHandler)(uintptr_t)slot;
 	handler_fn(*context);
 	context->resources.current_unit_file = previous_unit;
 }

src/wasm/worker.cpp

@@ -1090,7 +1090,7 @@ private:
 		}
 
 		if(!file_exists_host(worker.unit_wasm_path(resolved)) || compiler_unit_needs_recompile(context, resolved, 0))
-			get_shared_unit(context, resolved, true);
+			get_shared_unit(context, resolved);
 
 		size_t unit_index = 0;
 		String error = load_unit(resolved, unit_index);