feat(firewall-log): Phase 2 — HTTP-Tail + WebSocket-Live-Stream

Backend für /firewall-Live-Tail und historische Recherche der
ulogd2-JSONL aus Phase 1.

internal/services/firewalllog/
  reader.go  — JSONL parser + Filter (since/until/rule_id/src/dst/
               proto/action/limit). Proto-Mapping aus IP-Protocol-Number
               (1=icmp, 6=tcp, 17=udp, 58=icmpv6). RuleID wird aus
               oob.prefix "edgeguard:<id>" extrahiert.
  tailer.go  — fsnotify-Watcher auf /var/log/edgeguard/, In-Memory
               Ring-Buffer 1000 Events, fan-out an Subscribe()-Channel.
               Robust gegen logrotate copytruncate (truncate-detection
               via stat.Size() < offset → seek(0)). Safety-Net 2s-poll
               falls fsnotify einen Write verschluckt. Non-blocking send
               an Subscriber — langsame Clients droppen Events statt
               die Pipeline zu blockieren.

internal/handlers/firewall_log.go:
  GET /api/v1/firewall/log     — typed JSON list, Filter via Query
  WS  /api/v1/firewall/log/live — Snapshot + live broadcast
                                  (gorilla/websocket, 30s-ping)

main.go: Tailer beim Startup gestartet (context.Background) — UI
landet in Phase 3.

deps: gorilla/websocket v1.5.3, fsnotify v1.10.1

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

go.mod

@@ -3,8 +3,10 @@ module git.netcell-it.de/projekte/edgeguard-native
 go 1.26.0
 
 require (
+	github.com/fsnotify/fsnotify v1.10.1
 	github.com/gin-gonic/gin v1.10.0
 	github.com/go-acme/lego/v4 v4.35.2
+	github.com/gorilla/websocket v1.5.3
 	github.com/jackc/pgx/v5 v5.9.2
 	github.com/pressly/goose/v3 v3.27.1
 	github.com/skip2/go-qrcode v0.0.0-20200617195104-da1b6568686e