feat(mining): integrate mining subsystem into existing modules

- CMakeLists.txt: add 6 mining sources + tcp_transport dependency
- config.h/c: mining_payout_mode_t enum, mining config fields, JSON parsing
- tollgate_main.c: mining init in start_services(), stratum_client_tick in main loop
- tollgate_api.c: GET /mining/job, POST /mining/share, GET /mining/stats endpoints
- session.h/c: payment_method_t enum (CASHU/MINING/BYTES)
- firewall.h/c: sandbox allowlist for mining port + mint URLs
- tollgate_client.h/c: TG_CLIENT_MINING state, mining discovery tag parsing
- captive_portal.c: tabbed UI with Cashu/Mine tabs, live hashrate polling

1 files changed, 2 insertions, 0 deletions

diff --git a/main/session.c b/main/session.c
index 81e1f96..feea272 100644
--- a/main/session.c
+++ b/main/session.c
@@ -54,6 +54,7 @@ session_t *session_create(uint32_t client_ip, uint64_t allotment_ms)
             s_sessions[i].allotment_ms = allotment_ms;
             s_sessions[i].start_time_ms = get_time_ms();
             s_sessions[i].active = true;
+            s_sessions[i].payment_method = PAYMENT_METHOD_CASHU;
             populate_mac(&s_sessions[i], client_ip);
 
             s_session_count++;
@@ -78,6 +79,7 @@ session_t *session_create_bytes(uint32_t client_ip, uint64_t allotment_bytes)
         s->allotment_bytes = allotment_bytes;
         s->bytes_consumed = 0;
         s->allotment_ms = INT64_MAX;
+        s->payment_method = PAYMENT_METHOD_BYTES;
         esp_ip4_addr_t ip = { .addr = client_ip };
         ESP_LOGI(TAG, "Bytes session created: " IPSTR " allotment=%llu bytes", IP2STR(&ip),
                  (unsigned long long)allotment_bytes);