fix: rebase onto main, add IRC wire handlers and integration tests for Tier 3 commands

Rebase onto main to resolve conflicts from module path rename
(sneak.berlin/go/neoirc) and integration test addition.

- Update import paths in utility.go to new module path
- Add IRC wire protocol handlers for VERSION, ADMIN, INFO,
  TIME, KILL, and WALLOPS to ircserver/commands.go
- Register all 6 new commands in the IRC command dispatch map
- Implement proper user MODE +w/-w support for WALLOPS
- Add WALLOPS relay delivery in relay.go
- Add integration tests for all 7 Tier 3 commands:
  USERHOST, VERSION, ADMIN, INFO, TIME, KILL, WALLOPS
- Add newTestEnvWithOper helper for oper-dependent tests

internal/ircserver/conn.go

@@ -130,7 +130,13 @@ func (c *Conn) buildCommandMap() map[string]cmdHandler {
 		"CAP": func(_ context.Context, msg *Message) {
 			c.handleCAP(msg)
 		},
-		"USERHOST": c.handleUserhost,
+		"USERHOST":     c.handleUserhost,
+		irc.CmdVersion: func(ctx context.Context, _ *Message) { c.handleVersion(ctx) },
+		irc.CmdAdmin:   func(ctx context.Context, _ *Message) { c.handleAdmin(ctx) },
+		irc.CmdInfo:    func(ctx context.Context, _ *Message) { c.handleInfo(ctx) },
+		irc.CmdTime:    func(ctx context.Context, _ *Message) { c.handleTime(ctx) },
+		irc.CmdKill:    c.handleKillCmd,
+		irc.CmdWallops: c.handleWallopsCmd,
 	}
 }