Step 2.1: web server, embedded UI, /api/status, /api/reboot

- aes67_web: httpd (wildcard URI matching), serves web/index.html embedded
  via EMBED_TXTFILES, status registry (status_register) and route registry
  (web_register_uri), GET /api/status, POST /api/reboot (restarts 0.5 s
  after the response).
- Status fields come from each core component: aes67_net (ip, aes67_ip,
  mac, link), aes67_health (fw, uptime_s, heap_free, psram_free),
  aes67_tx stub (tx_packets, underruns = 0). No ptp object yet, so the UI
  shows "no data".
- Verified on board: / serves index.html byte-identical (27601 B),
  /api/status returns live values, reboot via API returns in ~12 s.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

components/aes67_web/CMakeLists.txt

@@ -1,2 +1,5 @@
 idf_component_register(SRCS "aes67_web.c"
-                       INCLUDE_DIRS "include")
+                       INCLUDE_DIRS "include"
+                       REQUIRES esp_http_server json
+                       PRIV_REQUIRES esp_timer
+                       EMBED_TXTFILES "${PROJECT_DIR}/web/index.html")

components/aes67_web/aes67_web.c

@@ -1,7 +1,122 @@
 #include "aes67_web.h"
 
-// Stub (build step 0).
-esp_err_t aes67_web_init(void)
+#include "esp_log.h"
+#include "esp_system.h"
+#include "esp_timer.h"
+
+#define MAX_STATUS_CBS  16
+#define MAX_URIS        32
+#define MAX_EARLY_URIS  16
+
+static const char *TAG = "web";
+
+extern const char index_html_start[] asm("_binary_index_html_start");
+extern const char index_html_end[] asm("_binary_index_html_end");
+
+static httpd_handle_t s_httpd;
+static status_cb_t s_status_cbs[MAX_STATUS_CBS];
+static int s_status_n;
+static httpd_uri_t s_early_uris[MAX_EARLY_URIS];
+static int s_early_n;
+
+esp_err_t status_register(status_cb_t cb)
 {
+    if (s_status_n >= MAX_STATUS_CBS) {
+        return ESP_ERR_NO_MEM;
+    }
+    s_status_cbs[s_status_n++] = cb;
+    return ESP_OK;
+}
+
+esp_err_t web_register_uri(const httpd_uri_t *uri)
+{
+    if (s_httpd) {
+        return httpd_register_uri_handler(s_httpd, uri);
+    }
+    if (s_early_n >= MAX_EARLY_URIS) {
+        return ESP_ERR_NO_MEM;
+    }
+    s_early_uris[s_early_n++] = *uri;
+    return ESP_OK;
+}
+
+esp_err_t web_send_json(httpd_req_t *req, const cJSON *json)
+{
+    char *body = cJSON_PrintUnformatted(json);
+    if (!body) {
+        return httpd_resp_send_err(req, HTTPD_500_INTERNAL_SERVER_ERROR, "out of memory");
+    }
+    httpd_resp_set_type(req, "application/json");
+    httpd_resp_set_hdr(req, "Cache-Control", "no-store");
+    esp_err_t err = httpd_resp_sendstr(req, body);
+    cJSON_free(body);
+    return err;
+}
+
+static esp_err_t index_get(httpd_req_t *req)
+{
+    httpd_resp_set_type(req, "text/html; charset=utf-8");
+    // EMBED_TXTFILES appends a NUL; don't send it.
+    return httpd_resp_send(req, index_html_start, index_html_end - index_html_start - 1);
+}
+
+static esp_err_t status_get(httpd_req_t *req)
+{
+    cJSON *st = cJSON_CreateObject();
+    for (int i = 0; i < s_status_n; i++) {
+        s_status_cbs[i](st);
+    }
+    esp_err_t err = web_send_json(req, st);
+    cJSON_Delete(st);
+    return err;
+}
+
+static void reboot_cb(void *arg)
+{
+    esp_restart();
+}
+
+static esp_err_t reboot_post(httpd_req_t *req)
+{
+    ESP_LOGW(TAG, "reboot requested via API");
+    httpd_resp_sendstr(req, "");
+    // Let the response go out before restarting.
+    const esp_timer_create_args_t args = { .callback = reboot_cb, .name = "reboot" };
+    esp_timer_handle_t t;
+    if (esp_timer_create(&args, &t) == ESP_OK) {
+        esp_timer_start_once(t, 500 * 1000);
+    }
+    return ESP_OK;
+}
+
+esp_err_t aes67_web_start(void)
+{
+    httpd_config_t cfg = HTTPD_DEFAULT_CONFIG();
+    cfg.max_uri_handlers = MAX_URIS;
+    cfg.stack_size = 8192;
+    cfg.lru_purge_enable = true;
+    cfg.uri_match_fn = httpd_uri_match_wildcard;
+
+    esp_err_t err = httpd_start(&s_httpd, &cfg);
+    if (err != ESP_OK) {
+        ESP_LOGE(TAG, "httpd start failed: %s", esp_err_to_name(err));
+        return err;
+    }
+
+    static const httpd_uri_t core[] = {
+        { .uri = "/",           .method = HTTP_GET,  .handler = index_get },
+        { .uri = "/index.html", .method = HTTP_GET,  .handler = index_get },
+        { .uri = "/api/status", .method = HTTP_GET,  .handler = status_get },
+        { .uri = "/api/reboot", .method = HTTP_POST, .handler = reboot_post },
+    };
+    for (int i = 0; i < sizeof(core) / sizeof(core[0]); i++) {
+        httpd_register_uri_handler(s_httpd, &core[i]);
+    }
+    for (int i = 0; i < s_early_n; i++) {
+        httpd_register_uri_handler(s_httpd, &s_early_uris[i]);
+    }
+
+    ESP_LOGI(TAG, "httpd started, index.html %d bytes, %d project routes",
+             (int)(index_html_end - index_html_start - 1), s_early_n);
     return ESP_OK;
 }

components/aes67_web/include/aes67_web.h

@@ -2,6 +2,19 @@
 // Core component: must not depend on main/ (project code).
 #pragma once
 
+#include "cJSON.h"
 #include "esp_err.h"
+#include "esp_http_server.h"
 
-esp_err_t aes67_web_init(void);
+// Adds fields to the /api/status object. Called on every GET /api/status.
+typedef void (*status_cb_t)(cJSON *status);
+
+// Registries: call before or after aes67_web_start(); routes registered early are added on start.
+esp_err_t status_register(status_cb_t cb);
+esp_err_t web_register_uri(const httpd_uri_t *uri);
+
+// Start httpd on port 80 with the core routes (/, /api/status, /api/reboot).
+esp_err_t aes67_web_start(void);
+
+// Send a cJSON object as the response body (application/json).
+esp_err_t web_send_json(httpd_req_t *req, const cJSON *json);