fix: revert .golangci.yml to main, fix all lint issues in code

- Restore original .golangci.yml from main (no linter config changes)
- Reduce complexity in dispatchCommand via command map pattern
- Extract helpers in api.go: respondError, internalError, normalizeChannel,
  handleCreateUserError, handleChangeNickError, partAndCleanup, broadcastTopic
- Split PollMessages into buildPollPath + decodePollResponse
- Add t.Parallel() to all tests, make subtests independent
- Extract test fx providers into named functions to reduce funlen
- Use mutex to serialize viper access in parallel tests
- Extract PRIVMSG constant, add nolint for gosec false positives
- Split long test functions into focused test cases
- Add blank lines before expressions per wsl_v5

cmd/chat-cli/main.go

@@ -123,36 +123,40 @@ func (a *App) handleCommand(text string) {
 }
 
 func (a *App) dispatchCommand(cmd, args string) {
-	switch cmd {
-	case "/connect":
-		a.cmdConnect(args)
-	case "/nick":
-		a.cmdNick(args)
-	case "/join":
-		a.cmdJoin(args)
-	case "/part":
-		a.cmdPart(args)
-	case "/msg":
-		a.cmdMsg(args)
-	case "/query":
-		a.cmdQuery(args)
-	case "/topic":
-		a.cmdTopic(args)
-	case "/names":
-		a.cmdNames()
-	case "/list":
-		a.cmdList()
-	case "/window", "/w":
-		a.cmdWindow(args)
-	case "/quit":
-		a.cmdQuit()
-	case "/help":
-		a.cmdHelp()
-	default:
-		a.ui.AddStatus(
-			"[red]Unknown command: " + cmd,
-		)
+	argCmds := map[string]func(string){
+		"/connect": a.cmdConnect,
+		"/nick":    a.cmdNick,
+		"/join":    a.cmdJoin,
+		"/part":    a.cmdPart,
+		"/msg":     a.cmdMsg,
+		"/query":   a.cmdQuery,
+		"/topic":   a.cmdTopic,
+		"/window":  a.cmdWindow,
+		"/w":       a.cmdWindow,
 	}
+
+	if fn, ok := argCmds[cmd]; ok {
+		fn(args)
+
+		return
+	}
+
+	noArgCmds := map[string]func(){
+		"/names": a.cmdNames,
+		"/list":  a.cmdList,
+		"/quit":  a.cmdQuit,
+		"/help":  a.cmdHelp,
+	}
+
+	if fn, ok := noArgCmds[cmd]; ok {
+		fn()
+
+		return
+	}
+
+	a.ui.AddStatus(
+		"[red]Unknown command: " + cmd,
+	)
 }
 
 func (a *App) cmdConnect(serverURL string) {