Complete Phase 12 dual-stack networking

Add IPv6-aware Wi-Fi state, HTTPS/SSH listeners, mDNS service
reconciliation, and browser Wi-Fi administration.

Include a guarded build-local fix for mDNS 1.12.0 membership handling,
focused regression suites, and Phase 12 acceptance documentation.

tests/wifi_phase12/run.py

@@ -0,0 +1,80 @@
+#!/usr/bin/env python3
+"""Compile verbatim manager address/deadline paths with bounded host fakes."""
+from pathlib import Path
+import subprocess
+import tempfile
+import sys
+
+HERE = Path(__file__).resolve().parent
+ROOT = HERE.parents[1]
+source = (ROOT / 'src/wifi_manager.c').read_text()
+
+def function(name):
+    # Definitions end at a column-zero brace; skip forward declarations.
+    import re
+    match = re.search(r'^static [^\n]+\b' + name + r'\([^;]*?\)\n\{', source, re.M)
+    assert match, name
+    start = match.start()
+    return source[start:source.index('\n}', match.end()) + 2]
+
+types = source[source.index('typedef enum {'):source.index('static SemaphoreHandle_t')]
+addresses = source[source.index('typedef struct {\n    esp_netif_ip_info_t ip4;'):source.index('/* IDF\'s IPv6 getters')]
+hostname_request = source[source.index('typedef struct {\n    const char *hostname;'):source.index('static esp_err_t set_station_hostname')]
+names = ['set_station_hostname', 'refresh_station_hostname', 'start_mdns_announcement',
+         'read_station_addresses', 'handle_got_ip', 'clear_station_network_snapshot',
+         'handle_expired_deadlines', 'next_runtime_deadline', 'runtime_wait_ticks',
+         'ip_event_callback']
+# Check wiring not present in the extracted paths.
+connect = function('start_next_profile')
+assert connect.index('refresh_station_hostname()') < connect.index('esp_wifi_connect()')
+message = function('handle_message')
+assert 'case MESSAGE_STA_GOT_IP6:' in message
+assert 'refresh_station_hostname()' in message
+assert 'handle_got_ip(runtime, message);' in message
+assert '#define WIFI_MANAGER_QUEUE_LENGTH 16U' in source
+assert '#define WIFI_MANAGER_TASK_STACK_SIZE 6144U' in source
+assert 'esp_netif_tcpip_exec(read_station_addresses, &addresses)' in source
+assert 'esp_netif_is_netif_up' not in function('handle_got_ip')
+assert 'mdns_service_reconcile()' in function('handle_expired_deadlines')
+assert 'runtime->radio_started ? runtime->reconcile_deadline' not in source
+for name in ['handle_sta_disconnected', 'mark_intentional_disconnect', 'stop_radio']:
+    assert 'clear_station_network_snapshot();' in function(name)
+
+with tempfile.TemporaryDirectory(prefix='wifi-phase12-') as directory:
+    tmp = Path(directory)
+    (tmp / 'esp_err.h').write_text('#pragma once\ntypedef int esp_err_t;\n#define ESP_OK 0\n#define ESP_FAIL -1\n#define ESP_ERR_INVALID_STATE 1\n#define ESP_ERR_INVALID_ARG 2\n')
+    (tmp / 'esp_wifi_types.h').write_text('#pragma once\ntypedef int wifi_auth_mode_t;\n')
+    # Use the installed IDF public address types/macros, not a reimplementation.
+    sdk_header = Path.home() / '.platformio/packages/framework-espidf/components/esp_netif/include/esp_netif_ip_addr.h'
+    (tmp / 'esp_netif_ip_addr.h').write_text(sdk_header.read_text())
+    (tmp / 'machine').mkdir()
+    (tmp / 'machine/endian.h').write_text('#include <endian.h>\n')
+    (tmp / 'sdkconfig.h').write_text('#define CONFIG_LWIP_IPV6 1\n')
+    (tmp / 'types.inc').write_text(types + addresses + hostname_request)
+    console = (ROOT / 'src/wifi_console.c').read_text()
+    start = console.index('static void print_ipv6_addresses(')
+    (tmp / 'console.inc').write_text(console[start:console.index('\n}', start) + 2])
+    assert 'print_ipv6_addresses(&snapshot);' in console
+    (tmp / 'production.inc').write_text('\n\n'.join(function(name) for name in names))
+    sanitizer = ['-fsanitize=address,undefined', '-fno-omit-frame-pointer'] if '--sanitize' in sys.argv else []
+    subprocess.run(['cc', '-std=gnu17', '-Wall', '-Wextra', '-Werror', *sanitizer,
+                    '-I' + str(tmp), '-I' + str(ROOT / 'src'), str(HERE / 'test.c'),
+                    '-o', str(tmp / 'test')], check=True, timeout=30)
+    subprocess.run([str(tmp / 'test')], check=True, timeout=20)
+    # Increasing SDK slots must fail compilation rather than truncate/overrun.
+    oversized = (HERE / 'test.c').read_text().replace('#define LWIP_IPV6_NUM_ADDRESSES 3', '#define LWIP_IPV6_NUM_ADDRESSES 4')
+    (tmp / 'oversized.c').write_text(oversized)
+    result = subprocess.run(['cc', '-std=gnu17', '-I' + str(tmp), '-I' + str(ROOT / 'src'),
+                             '-fsyntax-only', str(tmp / 'oversized.c')], capture_output=True, text=True)
+    assert result.returncode != 0 and 'IPv6 snapshot capacity' in result.stderr
+    print('IPv6 slot-capacity compile contract PASS')
+    header = (ROOT / 'src/wifi_manager.h').read_text()
+    baseline = header.replace('    uint8_t ipv6_count;\n', '').replace(
+        '    wifi_manager_ipv6_address_t ipv6_addresses[WIFI_MANAGER_IPV6_MAX_ADDRESSES];\n', '')
+    (tmp / 'baseline.h').write_text(baseline)
+    (tmp / 'sizes.c').write_text('#include <stdio.h>\n#include "baseline.h"\n'
+        'int main(void) { printf("baseline snapshot=%zu settings=%zu bytes\\n", '
+        'sizeof(wifi_manager_snapshot_t), sizeof(wifi_manager_settings_t)); }\n')
+    subprocess.run(['cc', '-I' + str(tmp), '-I' + str(ROOT / 'src'), str(tmp / 'sizes.c'),
+                    '-o', str(tmp / 'sizes')], check=True, timeout=30)
+    subprocess.run([str(tmp / 'sizes')], check=True, timeout=20)