feat: migrate INWX DNS CLI to interactive Textual TUI

- replace CLI menu with multi-panel Textual interface (sidebar & data table)
- implement asynchronous loading for domains and DNS records via worker threads
- add support for optional 2FA/TOTP auto-unlock and manual TAN modal
- introduce .env configuration fallback for stored credentials
- add modals for creating, editing, and deleting DNS records
- enable inline row editing via mouse double-click and keyboard navigation
- update project documentation in README.md

tui_modals.py

@@ -0,0 +1,125 @@
+#!/usr/bin/env python3
+"""INWX DNS TUI Client
+Author:  Pascal Bouquet <pascal@ptbos.de>
+License: GNU General Public License v3.0 (GPL-3.0)
+Year:    2026
+"""
+
+from textual.app import ComposeResult
+from textual.containers import Vertical, Horizontal
+from textual.widgets import Label, Input, Button, Select
+from textual.screen import ModalScreen
+
+RECORD_TYPES = [
+    ("A", "A"),
+    ("AAAA", "AAAA"),
+    ("CNAME", "CNAME"),
+    ("MX", "MX"),
+    ("TXT", "TXT"),
+    ("SRV", "SRV"),
+    ("CAA", "CAA"),
+    ("NS", "NS"),
+    ("PTR", "PTR"),
+    ("TLSA", "TLSA"),
+]
+
+class LoginModal(ModalScreen[tuple[str, str] | None]):
+    """Login-Maske bei fehlender oder fehlerhafter .env."""
+    def compose(self) -> ComposeResult:
+        with Vertical(classes="dialog-box"):
+            yield Label("🔐 INWX Login", classes="dialog-title")
+            yield Input(placeholder="Benutzername", id="user_input")
+            yield Input(placeholder="Passwort", password=True, id="pass_input")
+            with Horizontal(classes="dialog-buttons"):
+                yield Button("Einloggen", variant="primary", id="btn_submit", classes="modal-btn")
+                yield Button("Abbrechen", variant="error", id="btn_cancel", classes="modal-btn")
+
+    def on_button_pressed(self, event: Button.Pressed) -> None:
+        if event.button.id == "btn_submit":
+            user = self.query_one("#user_input", Input).value.strip()
+            pwd = self.query_one("#pass_input", Input).value.strip()
+            self.dismiss((user, pwd))
+        else:
+            self.dismiss(None)
+
+
+class TwoFactorModal(ModalScreen[str | None]):
+    """Fragt den 6-stelligen 2FA / TOTP-Code ab."""
+    def compose(self) -> ComposeResult:
+        with Vertical(classes="dialog-box"):
+            yield Label("🛡️ 2FA-Bestätigung", classes="dialog-title")
+            yield Label("6-stelligen TAN-Code eingeben:")
+            yield Input(placeholder="z.B. 123456", id="tan_input", max_length=6)
+            with Horizontal(classes="dialog-buttons"):
+                yield Button("Bestätigen", variant="primary", id="btn_submit_tan", classes="modal-btn")
+                yield Button("Abbrechen", variant="error", id="btn_cancel", classes="modal-btn")
+
+    def on_button_pressed(self, event: Button.Pressed) -> None:
+        if event.button.id == "btn_submit_tan":
+            tan = self.query_one("#tan_input", Input).value.strip()
+            self.dismiss(tan)
+        else:
+            self.dismiss(None)
+
+
+class RecordEditModal(ModalScreen[dict | None]):
+    """Dialog zum Anlegen und Bearbeiten von DNS-Records."""
+    def __init__(self, record: dict | None = None, default_domain: str = ""):
+        super().__init__()
+        self.record = record
+        self.default_domain = default_domain
+
+    def compose(self) -> ComposeResult:
+        is_edit = self.record is not None
+        title = f"Record ID {self.record['id']} bearbeiten" if is_edit else f"Neuer Record für {self.default_domain}"
+
+        with Vertical(classes="dialog-box"):
+            yield Label(title, classes="dialog-title")
+            
+            if not is_edit:
+                yield Label("Name / Host (@ oder z.B. mail):", classes="field-label")
+                yield Input(placeholder="@", value="@", id="rec_name")
+                
+                yield Label("Record-Typ (Auswählen oder eintippen):", classes="field-label")
+                with Horizontal(classes="type-row"):
+                    yield Select(
+                        RECORD_TYPES, 
+                        value="A", 
+                        prompt="Typ wählen", 
+                        id="rec_type_select",
+                        allow_blank=False
+                    )
+                    yield Input(value="A", placeholder="Typ", id="rec_type_input")
+
+            yield Label("Inhalt / Ziel:", classes="field-label")
+            val_content = str(self.record.get("content", "")) if is_edit else ""
+            yield Input(placeholder="z.B. IP, mx01.domain.tld, Text", value=val_content, id="rec_content")
+
+            yield Label("TTL (Sekunden):", classes="field-label")
+            val_ttl = str(self.record.get("ttl", "3600")) if is_edit else "3600"
+            yield Input(placeholder="3600", value=val_ttl, id="rec_ttl")
+
+            with Horizontal(classes="dialog-buttons"):
+                yield Button("Speichern", variant="success", id="btn_save", classes="modal-btn")
+                yield Button("Abbrechen", variant="error", id="btn_cancel", classes="modal-btn")
+
+    def on_select_changed(self, event: Select.Changed) -> None:
+        """Überträgt die Dropdown-Auswahl direkt in das Text-Eingabefeld."""
+        if event.select.id == "rec_type_select" and event.value != Select.BLANK:
+            type_input = self.query_one("#rec_type_input", Input)
+            type_input.value = str(event.value)
+
+    def on_button_pressed(self, event: Button.Pressed) -> None:
+        if event.button.id == "btn_save":
+            content = self.query_one("#rec_content", Input).value.strip()
+            ttl = self.query_one("#rec_ttl", Input).value.strip() or "3600"
+
+            if self.record:
+                data = {"content": content, "ttl": ttl}
+            else:
+                name = self.query_one("#rec_name", Input).value.strip()
+                rec_type = self.query_one("#rec_type_input", Input).value.strip().upper()
+                data = {"name": name, "type": rec_type, "content": content, "ttl": ttl}
+            self.dismiss(data)
+        else:
+            self.dismiss(None)