feat!: universal redesign — drop Minecraft stack, single-crate architecture

- remove Java plugins (velocity/paper), dashboard, all MC-specific code
  (handshake, death_code, varint, hostname-HMAC); available in history pre-v0.2
- merge crates/* into one package with src/bin/{rampart,rampart-manager,rampart-cli}
- ProtocolHandler trait + registry (no implementations yet), universal PoW kept
- XDP: universal L3/L4 filter (xdp/core/) + pluggable hook API (xdp/hooks/),
  fix IPv6 saddr bug; clang build verified
- docs: bilingual knowledge base (docs/kb/: attacks x4, defense-levels,
  practice x3), rewrite README/architecture for universal concept
- TODO.md v4.0: <=300-line module limit, competitor benchmark section (ref/)
- deploy/CI/docs cleanup: no MC references, new binary names

cargo build/clippy(-D warnings)/test green (55 tests)

deploy/test/stress/configs/edge-high.toml

@@ -3,11 +3,7 @@ address = "0.0.0.0"
 port = 25565
 
 [backend]
-address = "127.0.0.1"
-port = 25566
-
-[hmac]
-secret = "test_secret_32_bytes_long_for_integration_test"
+upstreams = ["127.0.0.1:25566"]
 
 [workers]
 count = 2
@@ -15,22 +11,18 @@ count = 2
 [limits]
 handshake_timeout_secs = 5
 max_connections_per_ip = 100000
-rate_limit_status_pps = 100000
-rate_limit_login_pps = 100000
-rate_limit_burst = 100000
+rate_limit_pps = 100000.0
+rate_limit_burst = 100000.0
 
 [store]
 redis_url = ""
 blacklist_cache_ttl_secs = 300
+clickhouse_url = ""
 
 [xdp]
 enabled = false
 interface = "eth0"
 
-[death_code]
-enabled = true
-ban_duration_secs = 3600
-
 [metrics]
 enabled = true
 port = 9090