feat(lws): add Kconfig toggles + bump submodule

Add three Kconfig options so consumers can tune libwebsockets without
forking this component:

  CONFIG_LWS_WITH_EXTENSIONS  (default n) — permessage-deflate / mux
  CONFIG_LWS_WITH_FILE_OPS    (default y) — server-side VFS layer
  CONFIG_LWS_WITH_THREADPOOL  (default n) — managed worker thread pool

Defaults preserve the previously-baked behaviour, so existing consumers
see zero change. AWS KVS WebRTC signaling — the immediate driver — flips
EXTENSIONS=y / FILE_OPS=n / THREADPOOL=y; with this PR those workloads
can consume espressif/libwebsockets from the registry instead of
carrying a local fork that twiddles the same knobs.

Also bumps the bundled libwebsockets submodule from a74362ff -> d659d4f2
(93 commits forward on the warmcat 4.3.x mainline). Picks up upstream
fixes (incl. the Linux-host build path landed via earlier espressif
contribution). No source-level patches on top — just the submodule pin.

Verified locally on esp32s3 with both default and KVS-flavour Kconfig:
configure clean; LWS_* CMake variables resolve correctly from Kconfig
(LWS_WITHOUT_EXTENSIONS / LWS_WITH_FILE_OPS / LWS_WITH_THREADPOOL all
follow the booleans).

components/libwebsockets/CMakeLists.txt

@@ -4,6 +4,27 @@ set(LWS_WITH_EXPORT_LWSTARGETS OFF CACHE BOOL "Export libwebsockets CMake target
 set(LWS_WITH_MBEDTLS ON CACHE BOOL "Use mbedTLS (>=2.0) replacement for OpenSSL.")
 set(LWS_WITH_JPEG OFF CACHE BOOL "Enable stateful JPEG stream decoder")
 
+# Kconfig-driven libwebsockets options. Defaults preserve the previous
+# behaviour (extensions off, file_ops on, threadpool off) so existing
+# consumers see no change. See Kconfig for help text and per-knob rationale.
+if(CONFIG_LWS_WITH_EXTENSIONS)
+    set(LWS_WITHOUT_EXTENSIONS OFF CACHE INTERNAL "Compile with extensions")
+else()
+    set(LWS_WITHOUT_EXTENSIONS ON  CACHE INTERNAL "Don't compile with extensions")
+endif()
+
+if(CONFIG_LWS_WITH_FILE_OPS)
+    set(LWS_WITH_FILE_OPS ON  CACHE INTERNAL "Support file operations vfs")
+else()
+    set(LWS_WITH_FILE_OPS OFF CACHE INTERNAL "Drop file operations vfs")
+endif()
+
+if(CONFIG_LWS_WITH_THREADPOOL)
+    set(LWS_WITH_THREADPOOL ON  CACHE INTERNAL "Managed worker thread pool support")
+else()
+    set(LWS_WITH_THREADPOOL OFF CACHE INTERNAL "No worker thread pool")
+endif()
+
 
 set(WRAP_FUNCTIONS mbedtls_ssl_handshake_step
                    lws_adopt_descriptor_vhost)
@@ -18,3 +39,6 @@ target_sources(${COMPONENT_LIB} INTERFACE "port/lws_port.c")
 
 
 add_subdirectory(libwebsockets)
+
+# pollfd.c at this lws pin has an unused 'vpt' on FreeRTOS; drop after the next bump.
+target_compile_options(websockets PRIVATE -Wno-unused-variable)

components/libwebsockets/Kconfig

@@ -0,0 +1,35 @@
+menu "libwebsockets"
+
+    # All defaults below preserve the previously-baked behaviour
+    # (extensions off, file_ops on, threadpool off). Flip them to suit
+    # the workload — e.g. WebRTC signaling consumers enable extensions
+    # for permessage-deflate and threadpool for parallel TLS work.
+
+    config LWS_WITH_EXTENSIONS
+        bool "Build libwebsockets with extensions (permessage-deflate, mux)"
+        default n
+        help
+            Enables LWS extensions support. Required for clients/servers
+            that negotiate permessage-deflate or other RFC 7692 extensions
+            over the WebSocket handshake. Requires LWS_WITH_ZLIB at link
+            time, which the ESP-IDF mbedTLS build does not pull in by
+            default — you'll need to add zlib as a dependency.
+
+    config LWS_WITH_FILE_OPS
+        bool "Build libwebsockets with the file-operations VFS"
+        default y
+        help
+            Compiles the libwebsockets virtual filesystem layer used by
+            server-side static file serving. Disable on embedded targets
+            that don't expose a real filesystem to lws to save flash.
+
+    config LWS_WITH_THREADPOOL
+        bool "Build libwebsockets with the worker threadpool API"
+        default n
+        help
+            Enables lws's managed worker thread pool (pthread-backed).
+            Used by clients that want to off-load parallel TLS handshake
+            or other work from the lws service thread (e.g. AWS KVS
+            WebRTC signaling). Costs a few hundred bytes of static data.
+
+endmenu