Phase 4: TollGate client detection + auto-payment

- New tollgate_client.c/h: detect upstream TollGate (kind=10021),
  auto-pay via nucula wallet, session monitoring with 20% renewal
- State machine: IDLE→DETECTING→NEEDS_PAY→PAYING→PAID→RENEWING
- Blocking: upstream payment before local services start
- Synchronous wallet init (was async task)
- Client config: enabled, steps_to_buy, renewal_threshold_pct
- Updated PLAN.md with Phases 4-7 (client, payout, bytes, CVM)
- Updated CHECKLIST.md with all new phase items
- 30 new unit tests (all passing), 116 total

1 files changed, 4 insertions, 1 deletions

diff --git a/tests/unit/Makefile b/tests/unit/Makefile
index ab41175..e4ea388 100644
--- a/tests/unit/Makefile
+++ b/tests/unit/Makefile
@@ -21,7 +21,7 @@ LDFLAGS := -lmbedcrypto -lcjson
 
 SECP256K1_OBJ := secp256k1.o precomputed_ecmult.o precomputed_ecmult_gen.o
 
-TESTS := test_geohash test_identity test_nostr_event test_cashu test_session
+TESTS := test_geohash test_identity test_nostr_event test_cashu test_session test_tollgate_client
 
 .PHONY: all test clean $(TESTS)
 
@@ -62,5 +62,8 @@ test_cashu: test_cashu.c $(REPO_ROOT)/main/cashu.c
 test_session: test_session.c $(REPO_ROOT)/main/session.c
         $(CC) $(CFLAGS) $< $(REPO_ROOT)/main/session.c -o $@ $(LDFLAGS)
 
+test_tollgate_client: test_tollgate_client.c
+        $(CC) $(CFLAGS) $< -o $@ $(LDFLAGS)
+
 clean:
         rm -f $(TESTS) $(SECP256K1_OBJ)