feat: ContextVM (MCP over Nostr) server with full integration

Complete CVM implementation: persistent WebSocket relay listener,
kind 25910 event subscription, MCP protocol handlers, CEP-6 announcements,
10 MCP tools, per-board hardware locks, WiFi EU regulatory fix.

Architecture:
- cvm_server.c: WS relay listener, kind 25910 subscription, MCP dispatch
- mcp_handler.c/h: 10 MCP tools (get_config, set_config, get_balance,
  wallet_send, get_sessions, get_usage, set_payout, set_metric,
  set_price, wallet_melt)
- Responses published via existing WS connection (not new TLS)
- Auth check: only owner npub accepted
- CEP-6: kinds 11316 (server), 11317 (tools), 10002 (relay list)
- WS ping/pong keepalive every 30s, 60s TLS read timeout

Critical fixes:
- WiFi country code DE (ESP-IDF defaults to CN, breaks EU APs)
- Subscription #p filter must be array not string
- Use-after-free: tags_str freed before nostr_event_to_json
- MCP responses via existing WS (ESP32 can't open multiple TLS)
- EVENT msg buffer underflow, WS frame masking, TLS write loop

Per-board hardware locks:
- Lock files in physical-router-test-automation/locks/
- lock-a/b/c, unlock-a/b/c targets in 3 Makefiles
- All hardware-touching targets require board lock

Verified on Board B via relay.primal.net:
- 282 unit tests passing (61 CVM + 60 MCP + 161 existing)
- MCP initialize roundtrip: PASS
- tools/list: PASS
- tools/call get_config: PASS
- tools/call get_balance: PASS
- tools/call set_price: PASS (write operation)
- CEP-6 announcements (11316, 11317, 10002): all accepted by relay
- WiFi STA connection (EnterSSID-2.4GHz): PASS with country code DE
- Board A WiFi confirmed hardware issue (not firmware)

1 files changed, 4 insertions, 1 deletions

diff --git a/tests/unit/Makefile b/tests/unit/Makefile
index 5dee0d7..7ebc3b2 100644
--- a/tests/unit/Makefile
+++ b/tests/unit/Makefile
@@ -22,7 +22,7 @@ LDFLAGS := -lmbedcrypto -lcjson -lm
 
 SECP256K1_OBJ := secp256k1.o precomputed_ecmult.o precomputed_ecmult_gen.o
 
-TESTS := test_geohash test_identity test_nostr_event test_cashu test_session test_tollgate_client test_lnurl_pay test_lightning_payout test_mcp_handler test_nip04
+TESTS := test_geohash test_identity test_nostr_event test_cashu test_session test_tollgate_client test_lnurl_pay test_lightning_payout test_mcp_handler test_nip04 test_cvm_server
 
 .PHONY: all test clean $(TESTS)
 
@@ -78,5 +78,8 @@ test_mcp_handler: test_mcp_handler.c $(REPO_ROOT)/main/mcp_handler.c
 test_nip04: test_nip04.c $(REPO_ROOT)/main/nip04.c $(SECP256K1_OBJ)
         $(CC) $(CFLAGS) -I $(SECP256K1_PRIV_INC) $< $(REPO_ROOT)/main/nip04.c $(SECP256K1_OBJ) -o $@ $(LDFLAGS)
 
+test_cvm_server: test_cvm_server.c
+        $(CC) $(CFLAGS) $< -o $@ $(LDFLAGS)
+
 clean:
         rm -f $(TESTS) $(SECP256K1_OBJ)