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, 27 insertions, 0 deletions

diff --git a/main/stratum_client.h b/main/stratum_client.h
new file mode 100644
index 0000000..e143439
--- /dev/null
+++ b/main/stratum_client.h
@@ -0,0 +1,27 @@
+#ifndef STRATUM_CLIENT_H
+#define STRATUM_CLIENT_H
+
+#include "esp_err.h"
+#include "stratum_proxy.h"
+#include <stdint.h>
+#include <stdbool.h>
+
+typedef struct {
+    bool connected;
+    char pool_host[128];
+    uint16_t pool_port;
+    uint32_t nbits;
+    uint64_t difficulty;
+    uint64_t shares_accepted;
+    uint64_t shares_rejected;
+    bool sv2_active;
+} stratum_client_state_t;
+
+esp_err_t stratum_client_init(void);
+esp_err_t stratum_client_start(void);
+void stratum_client_stop(void);
+esp_err_t stratum_client_submit_share(uint32_t job_id, uint32_t nonce, uint32_t ntime, uint32_t version);
+const stratum_client_state_t *stratum_client_get_state(void);
+void stratum_client_tick(void);
+
+#endif