Captive portal detection fix + Phase 2 tests 16-18,20 passing (17/17)

- Add DoT reject server on port 853 (TCP RST forces DNS-over-TLS fallback)
- DNS hijack returns NXDOMAIN for all non-A query types (no forwarding for unauthed)
- Shorter TTL on hijack responses (10s) for faster captive detection
- Explicit 302 redirect handlers for /generate_204, /hotspot-detect.html, etc.
- HTTP and DNS request logging for debugging captive detection
- Per-MAC tracking in firewall (find_by_mac, get_mac_for_ip with ARP fallback)
- Session MAC tracking (session_find_by_mac)
- Phase 2 test 18: add route through TollGate before ping test
- All 17 Phase 2 tests pass (15-21 + whoami + portal form)

1 files changed, 1 insertions, 0 deletions

diff --git a/main/session.h b/main/session.h
index e7d78d4..8e2d48d 100644
--- a/main/session.h
+++ b/main/session.h
@@ -24,6 +24,7 @@ session_t *session_create(uint32_t client_ip, uint64_t allotment_ms,
                           const char *spent_secrets[], int secret_count);
 
 session_t *session_find_by_ip(uint32_t client_ip);
+session_t *session_find_by_mac(const char *mac);
 
 void session_extend(session_t *session, uint64_t additional_ms);