feat: add support for insecure mode in Gitea client configuration (#20)

- Add `GITEA_INTERACTIVE` configuration example in README files
- Add `insecure` flag to ignore TLS certificate errors in `cmd.go`
- Set insecure mode based on `GITEA_INSECURE` environment variable in `cmd.go`
- Add `Insecure` boolean variable in `pkg/flag/flag.go`
- Import `crypto/tls` and `net/http` in `pkg/gitea/gitea.go`
- Modify Gitea client creation to support insecure HTTP client in `pkg/gitea/gitea.go`

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

Reviewed-on: https://gitea.com/gitea/gitea-mcp/pulls/20
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: Bo-Yi Wu <appleboy.tw@gmail.com>
Co-committed-by: Bo-Yi Wu <appleboy.tw@gmail.com>

cmd/cmd.go

@@ -62,6 +62,12 @@ func init() {
 		true,
 		"debug mode",
 	)
+	flag.BoolVar(
+		&flagPkg.Insecure,
+		"insecure",
+		false,
+		"ignore TLS certificate errors",
+	)
 
 	flag.Parse()
 
@@ -88,6 +94,11 @@ func init() {
 	if !debug {
 		flagPkg.Debug = os.Getenv("GITEA_DEBUG") == "true"
 	}
+
+	// Set insecure mode based on environment variable
+	if os.Getenv("GITEA_INSECURE") == "true" {
+		flagPkg.Insecure = true
+	}
 }
 
 func Execute(version string) {