Merge upstream/main into feat/webui-compression

Resolve conflicts against ~55 upstream commits since 37eefb4:
- Makefile: keep upstream parallel-build fixes (machine_init.c, SUBDIRSCLEAN, html_data grouped target) and retain minify+gzip pipeline (-z, html_min, .css/.ico)
- tools: retain gzip support (zlib, -lz) lost in upstream revert
- httpd/httpd.c: keep Content-Encoding: gzip alongside upstream GET walk, config upload, syslog/hostname changes
- html: port upstream HTML/JS changes into SPA (single-page) bundle:
  * i18n: add port_col_devices / port_devices keys (en/ja/zh)
  * ports: add Connected devices column, devRender/devWalk via walkL2 (8c3df64)
  * config: add syslog port, extended stp/igmp/bw patterns, conf_toggle handling
  * system: show /cmd output in console (console_out), 401 handling
  * l2: hide delete for CPU entry, delL2Button, sort/filter improvements
  * navigation: add STP entry
- SPA: integrate new STP page (stp.html/js) as page-stp section with sectionInits.stp, bridge/prio handling, per-port config/status tables
- Remove per-page HTML/JS files (now bundled) and standalone stp.html/js

Verified: tools build, html_min generation (main.js 93k->81k->19k gzip, 8 files), html_data.h gzip sizes, main.js syntax check.

Makefile

@@ -53,6 +53,7 @@ create_build_dir:
 # Keep machine.c in first position to fail immediately on invalid $MACHINE value
 SRCS = \
 	machine.c \
+	machine_init.c \
 	cmd_editor.c \
 	cmd_parser.c \
 	dhcp.c \
@@ -112,14 +113,17 @@ httpd: html_data.h
 $(SUBDIRS):
 	$(MAKE) -C $@
 
-clean:
+clean: $(SUBDIRSCLEAN)
 	-rm -f html_data.c html_data.h $(VERSION_HEADER)
 	-if [ -d $(BUILDDIR) ]; then find $(BUILDDIR) -type f ! -name "*.bin" -delete; fi
 
-distclean:
+distclean: $(SUBDIRSCLEAN)
 	-rm -f html_data.c html_data.h $(VERSION_HEADER)
 	-rm -rf $(BUILDDIR)
 
+$(SUBDIRSCLEAN):
+	$(MAKE) -C $(@:clean=) clean
+
 $(BUILDDIR)/%.rel: %.c | create_build_dir html_data.h
 	$(CC) -MMD $(CC_FLAGS) -o $@ -c $<
 
@@ -142,16 +146,17 @@ $(BUILDDIR)/rtlplayground-$(FILENAME_EXTENSION).bin: $(BUILDDIR)/rtlplayground.i
 	tools/output/crc_calculator -u $@
 	ln -sf $(MACHINE)/rtlplayground-$(FILENAME_EXTENSION).bin output/rtlplayground.bin
 
-.PHONY: clean all $(SUBDIRS) $(VERSION_HEADER) create_build_dir
+.PHONY: clean distclean all $(SUBDIRS) $(SUBDIRSCLEAN) $(VERSION_HEADER) create_build_dir
 
 .PHONY:
 machine_check:
 	@mkdir -p $(BUILDDIR)/tmp
 	@set -eo pipefail; \
-	for MACHINE in `grep -e ' MACHINE_' machine.c | sed -e 's%^.* MACHINE_%%' -e 's%[ ]*//.*$$%%' | sort -u`; \
+	for MACHINE in `grep -E '^[[:space:]]*(//[[:space:]]*)?#define MACHINE_' machine.h | sed -E 's%^[[:space:]]*(//[[:space:]]*)?#define MACHINE_%%' | awk '{print $$1}' | sort -u`; \
 	do \
 	echo "Checking $${MACHINE}"; \
 	$(CC) $(CC_FLAGS) -DMACHINE_$${MACHINE} -MMD -o $(BUILDDIR)/tmp/machine_check -c machine.c; \
+	$(CC) $(CC_FLAGS) -DMACHINE_$${MACHINE} -MMD -o $(BUILDDIR)/tmp/machine_check -c machine_init.c; \
 	done
 	@rm -rf $(BUILDDIR)/tmp