feat(mining): add new mining source files and unit tests

- mining_payment.c/h: hashprice calc, share validation, per-client hashrate
- stratum_client.c/h: SV1 upstream pool connection
- stratum_proxy.c/h: local SV1 TCP server for downstream miners
- sw_miner.c/h: software SHA256d miner using mbedtls
- asic_miner.c/h: ASIC detection stub (software fallback)
- test_mining_payment.c: 23 unit tests for mining payment module

1 files changed, 111 insertions, 0 deletions

diff --git a/main/sw_miner.c b/main/sw_miner.c
new file mode 100644
index 0000000..b45e7c5
--- /dev/null
+++ b/main/sw_miner.c
@@ -0,0 +1,111 @@
+#include "sw_miner.h"
+#include "stratum_proxy.h"
+#include "stratum_client.h"
+#include "mining_payment.h"
+#include "config.h"
+#include "esp_log.h"
+#include "mbedtls/sha256.h"
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include <string.h>
+
+static const char *TAG = "sw_miner";
+static bool s_running = false;
+static TaskHandle_t s_task_handle = NULL;
+static double s_hashrate = 0.0;
+
+static void sha256d(const uint8_t *data, size_t len, uint8_t *hash)
+{
+    uint8_t tmp[32];
+    mbedtls_sha256(data, len, tmp, 0);
+    mbedtls_sha256(tmp, 32, hash, 0);
+}
+
+static void sw_miner_task(void *arg)
+{
+    ESP_LOGI(TAG, "Software miner started");
+
+    uint64_t hashes = 0;
+    int64_t start_time = (int64_t)xTaskGetTickCount() * portTICK_PERIOD_MS;
+
+    uint8_t header[80];
+    uint8_t hash[32];
+
+    while (s_running) {
+        const stratum_job_t *job = stratum_proxy_get_current_job();
+        if (!job || !job->valid) {
+            vTaskDelay(pdMS_TO_TICKS(1000));
+            continue;
+        }
+
+        stratum_job_t local_job;
+        memcpy(&local_job, job, sizeof(stratum_job_t));
+
+        memcpy(header, local_job.prevhash, 32);
+        memcpy(header + 32, local_job.merkle_root, 32);
+
+        uint32_t start_nonce = esp_random();
+        uint32_t end_nonce = start_nonce + 1000;
+
+        for (uint32_t nonce = start_nonce; nonce < end_nonce && s_running; nonce++) {
+            header[76] = (nonce >> 0) & 0xFF;
+            header[77] = (nonce >> 8) & 0xFF;
+            header[78] = (nonce >> 16) & 0xFF;
+            header[79] = (nonce >> 24) & 0xFF;
+
+            sha256d(header, 80, hash);
+            hashes++;
+
+            if (memcmp(hash, local_job.target, local_job.target_len) <= 0) {
+                ESP_LOGI(TAG, "Valid share found! nonce=%08lx", (unsigned long)nonce);
+                stratum_client_submit_share(local_job.job_id, nonce, local_job.ntime, local_job.version);
+                mining_update_hashrate(0, true);
+                break;
+            }
+        }
+
+        int64_t now = (int64_t)xTaskGetTickCount() * portTICK_PERIOD_MS;
+        int64_t elapsed_s = (now - start_time) / 1000;
+        if (elapsed_s > 0) {
+            s_hashrate = (double)hashes / (double)elapsed_s / 1e6;
+        }
+
+        taskYIELD();
+    }
+
+    vTaskDelete(NULL);
+}
+
+esp_err_t sw_miner_start(void)
+{
+    if (s_running) return ESP_OK;
+    s_running = true;
+    s_hashrate = 0.0;
+
+    BaseType_t ret = xTaskCreate(sw_miner_task, "sw_miner", 8192, NULL, 2, &s_task_handle);
+    if (ret != pdPASS) {
+        ESP_LOGE(TAG, "Failed to create sw_miner task");
+        s_running = false;
+        return ESP_FAIL;
+    }
+    return ESP_OK;
+}
+
+void sw_miner_stop(void)
+{
+    s_running = false;
+    if (s_task_handle) {
+        vTaskDelay(pdMS_TO_TICKS(500));
+        s_task_handle = NULL;
+    }
+}
+
+bool sw_miner_is_running(void)
+{
+    return s_running;
+}
+
+double sw_miner_get_hashrate(void)
+{
+    return s_hashrate;
+}