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, 39 insertions, 0 deletions

diff --git a/main/stratum_proxy.h b/main/stratum_proxy.h
new file mode 100644
index 0000000..b940640
--- /dev/null
+++ b/main/stratum_proxy.h
@@ -0,0 +1,39 @@
+#ifndef STRATUM_PROXY_H
+#define STRATUM_PROXY_H
+
+#include "esp_err.h"
+#include <stdint.h>
+#include <stdbool.h>
+
+#define STRATUM_MAX_JOB_ID_LEN 32
+#define STRATUM_MAX_JOBS 4
+
+typedef struct {
+    uint32_t job_id;
+    uint8_t prevhash[32];
+    uint8_t merkle_root[32];
+    uint32_t ntime;
+    uint32_t nbits;
+    uint32_t version;
+    uint8_t target[32];
+    int target_len;
+    bool valid;
+} stratum_job_t;
+
+typedef struct {
+    double hashrate_ghs;
+    uint32_t nbits;
+    uint64_t total_shares;
+    uint64_t total_accepted;
+    uint64_t total_rejected;
+    double current_hashprice;
+    int active_miners;
+} stratum_proxy_stats_t;
+
+esp_err_t stratum_proxy_init(uint16_t port);
+void stratum_proxy_set_job(const stratum_job_t *job);
+const stratum_job_t *stratum_proxy_get_current_job(void);
+void stratum_proxy_get_stats(stratum_proxy_stats_t *stats);
+void stratum_proxy_stop(void);
+
+#endif