feat: upgrade tollgate_core to full version with mining + stratum

Replace skeleton tollgate_core (9 files, 7 callbacks) with full version
from feature/miner-integration (13 files, 22 callbacks):

New modules:
- tollgate_core_mining.c/h — mining payment session management
- tollgate_core_stratum_proxy.c/h — SV1 stratum proxy

Updated:
- tollgate_core.h — extern C guards, 5 new mining API functions
- tollgate_platform.h — extern C guards, 22 platform callbacks (was 7)
- tollgate_core_firewall.c — conditional CONFIG_LWIP_IPV4_NAPT
- CMakeLists.txt — mining + stratum source files

Also adds MINER_INTEGRATION_PLAN.md from the feature branch.

2 files changed, 34 insertions, 0 deletions

diff --git a/components/tollgate_core/include/tollgate_core.h b/components/tollgate_core/include/tollgate_core.h
index c47ebeb..6a17cbd 100644
--- a/components/tollgate_core/include/tollgate_core.h
+++ b/components/tollgate_core/include/tollgate_core.h
@@ -7,6 +7,10 @@
 #include <stdbool.h>
 #include <stdint.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 esp_err_t tollgate_core_init(const tollgate_platform_t *platform, esp_ip4_addr_t ap_ip);
 
 esp_err_t tollgate_core_dns_start(esp_ip4_addr_t upstream_dns);
@@ -31,4 +35,14 @@ int tollgate_core_allowed_client_count(void);
 bool tollgate_core_is_owner(uint32_t client_ip);
 bool tollgate_core_is_owner_connected(void);
 
+esp_err_t tollgate_core_stratum_proxy_init(uint16_t port);
+void tollgate_core_stratum_proxy_stop(void);
+void tollgate_core_on_share_accepted(uint32_t client_ip, double difficulty);
+double tollgate_core_calc_hashprice(double hashrate_ghs);
+char *tollgate_core_get_mining_status_json(void);
+
+#ifdef __cplusplus
+}
+#endif
+
 #endif
diff --git a/components/tollgate_core/include/tollgate_platform.h b/components/tollgate_core/include/tollgate_platform.h
index f60f1f9..79e25cf 100644
--- a/components/tollgate_core/include/tollgate_platform.h
+++ b/components/tollgate_core/include/tollgate_platform.h
@@ -4,6 +4,10 @@
 #include <stdint.h>
 #include <stdbool.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef struct {
     uint16_t     (*get_price_sats)(void);
     int32_t      (*get_step_ms)(void);
@@ -12,6 +16,22 @@ typedef struct {
     int32_t      (*get_step_bytes)(void);
     int64_t      (*get_time_ms)(void);
     bool         (*spend_proofs)(const char *raw_token_json);
+
+    const char * (*get_stratum_url)(void);
+    uint16_t     (*get_stratum_port)(void);
+    const char * (*get_stratum_user)(void);
+    const char * (*get_stratum_pass)(void);
+    const char * (*get_stratum_fallback_url)(void);
+    uint16_t     (*get_stratum_fallback_port)(void);
+    uint16_t     (*get_mining_port)(void);
+    const char * (*get_mining_payout_mode)(void);
+    uint64_t     (*get_hashprice_sats_per_ghs_day)(void);
+    void         (*on_share_accepted)(double difficulty);
+    double       (*get_hashrate)(void);
 } tollgate_platform_t;
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif