feat: add get_current_time built-in tool and timezone config

Fetches real time via HTTP Date header (works through proxy),
sets system clock, and returns formatted local time to the agent.
Also adds MIMI_TIMEZONE config and updates default model to claude-opus-4-5.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

main/tools/tool_get_time.c

@@ -0,0 +1,161 @@
+#include "tool_get_time.h"
+#include "mimi_config.h"
+#include "proxy/http_proxy.h"
+
+#include <string.h>
+#include <stdlib.h>
+#include <time.h>
+#include <sys/time.h>
+#include "esp_log.h"
+#include "esp_http_client.h"
+#include "esp_crt_bundle.h"
+
+static const char *TAG = "tool_time";
+
+static const char *MONTHS[] = {
+    "Jan","Feb","Mar","Apr","May","Jun",
+    "Jul","Aug","Sep","Oct","Nov","Dec"
+};
+
+/* Parse "Sat, 01 Feb 2025 10:25:00 GMT" → set system clock, return formatted string */
+static bool parse_and_set_time(const char *date_str, char *out, size_t out_size)
+{
+    int day, year, hour, min, sec;
+    char mon_str[4] = {0};
+
+    if (sscanf(date_str, "%*[^,], %d %3s %d %d:%d:%d",
+               &day, mon_str, &year, &hour, &min, &sec) != 6) {
+        return false;
+    }
+
+    int mon = -1;
+    for (int i = 0; i < 12; i++) {
+        if (strcmp(mon_str, MONTHS[i]) == 0) { mon = i; break; }
+    }
+    if (mon < 0) return false;
+
+    struct tm tm = {
+        .tm_sec = sec, .tm_min = min, .tm_hour = hour,
+        .tm_mday = day, .tm_mon = mon, .tm_year = year - 1900,
+    };
+
+    /* Convert UTC to epoch — mktime expects local, so temporarily set UTC */
+    setenv("TZ", "UTC0", 1);
+    tzset();
+    time_t t = mktime(&tm);
+
+    /* Restore timezone */
+    setenv("TZ", MIMI_TIMEZONE, 1);
+    tzset();
+
+    if (t < 0) return false;
+
+    struct timeval tv = { .tv_sec = t };
+    settimeofday(&tv, NULL);
+
+    /* Format in local time */
+    struct tm local;
+    localtime_r(&t, &local);
+    strftime(out, out_size, "%Y-%m-%d %H:%M:%S %Z (%A)", &local);
+
+    return true;
+}
+
+/* Fetch time via proxy: HEAD request to api.telegram.org, parse Date header */
+static esp_err_t fetch_time_via_proxy(char *out, size_t out_size)
+{
+    proxy_conn_t *conn = proxy_conn_open("api.telegram.org", 443, 10000);
+    if (!conn) return ESP_ERR_HTTP_CONNECT;
+
+    const char *req =
+        "HEAD / HTTP/1.1\r\n"
+        "Host: api.telegram.org\r\n"
+        "Connection: close\r\n\r\n";
+
+    if (proxy_conn_write(conn, req, strlen(req)) < 0) {
+        proxy_conn_close(conn);
+        return ESP_ERR_HTTP_WRITE_DATA;
+    }
+
+    char buf[1024];
+    int total = 0;
+    while (total < (int)sizeof(buf) - 1) {
+        int n = proxy_conn_read(conn, buf + total, sizeof(buf) - 1 - total, 10000);
+        if (n <= 0) break;
+        total += n;
+        buf[total] = '\0';
+        if (strstr(buf, "\r\n\r\n")) break;
+    }
+    proxy_conn_close(conn);
+
+    /* Find Date header */
+    char *date_hdr = strcasestr(buf, "\r\nDate: ");
+    if (!date_hdr) return ESP_ERR_NOT_FOUND;
+    date_hdr += 8;
+
+    char *eol = strstr(date_hdr, "\r\n");
+    if (!eol) return ESP_ERR_NOT_FOUND;
+
+    char date_val[64];
+    size_t dlen = eol - date_hdr;
+    if (dlen >= sizeof(date_val)) return ESP_ERR_NOT_FOUND;
+    memcpy(date_val, date_hdr, dlen);
+    date_val[dlen] = '\0';
+
+    if (!parse_and_set_time(date_val, out, out_size)) return ESP_FAIL;
+    return ESP_OK;
+}
+
+/* Fetch time via direct HTTPS */
+static esp_err_t fetch_time_direct(char *out, size_t out_size)
+{
+    esp_http_client_config_t config = {
+        .url = "https://api.telegram.org/",
+        .method = HTTP_METHOD_HEAD,
+        .timeout_ms = 10000,
+        .crt_bundle_attach = esp_crt_bundle_attach,
+    };
+
+    esp_http_client_handle_t client = esp_http_client_init(&config);
+    if (!client) return ESP_FAIL;
+
+    esp_err_t err = esp_http_client_perform(client);
+    if (err != ESP_OK) {
+        esp_http_client_cleanup(client);
+        return err;
+    }
+
+    /* Get Date header */
+    char date_val[64] = {0};
+    err = esp_http_client_get_header(client, "Date", (char **)&date_val);
+    /* esp_http_client_get_header returns pointer, not copy */
+    char *date_ptr = NULL;
+    esp_http_client_get_header(client, "Date", &date_ptr);
+    esp_http_client_cleanup(client);
+
+    if (!date_ptr || date_ptr[0] == '\0') return ESP_ERR_NOT_FOUND;
+
+    if (!parse_and_set_time(date_ptr, out, out_size)) return ESP_FAIL;
+    return ESP_OK;
+}
+
+esp_err_t tool_get_time_execute(const char *input_json, char *output, size_t output_size)
+{
+    ESP_LOGI(TAG, "Fetching current time...");
+
+    esp_err_t err;
+    if (http_proxy_is_enabled()) {
+        err = fetch_time_via_proxy(output, output_size);
+    } else {
+        err = fetch_time_direct(output, output_size);
+    }
+
+    if (err == ESP_OK) {
+        ESP_LOGI(TAG, "Time: %s", output);
+    } else {
+        snprintf(output, output_size, "Error: failed to fetch time (%s)", esp_err_to_name(err));
+        ESP_LOGE(TAG, "%s", output);
+    }
+
+    return err;
+}