feat: SFTP-Anbindung und Zugangsdatenart im Datenmodell

Neuer Anbindungstyp sftp (share = entfernter Basispfad, port, host_key),
credentials.kind (password|ssh_key) und public_key. Migration 0001 vor
dem ersten Release angepasst.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

pyproject.toml

@@ -24,6 +24,7 @@ dependencies = [
     "pydantic-settings>=2.3",
     "itsdangerous>=2.2",
     "httpx>=0.27",
+    "paramiko>=3.4",
 ]
 
 [project.optional-dependencies]
@@ -31,6 +32,7 @@ dev = [
     "pytest>=8.2",
     "ruff>=0.6",
     "mypy>=1.11",
+    "types-paramiko",
 ]
 
 [project.scripts]
@@ -52,14 +54,14 @@ target-version = "py312"
 src = ["src", "tests"]
 
 [tool.ruff.lint]
-select = ["E", "F", "W", "I", "B", "UP", "S", "SIM", "RUF", "PTH"]
+select = ["E", "F", "W", "I", "B", "UP", "S", "SIM", "RUF"]
 ignore = [
     "S603", # subprocess ohne shell=True ist genau das gewünschte Muster
     "RUF001", "RUF002", "RUF003", # deutsche Texte mit Typografie
 ]
 
 [tool.ruff.lint.per-file-ignores]
-"tests/**" = ["S101", "S105", "S106", "S108"]
+"tests/**" = ["S101", "S105", "S106", "S107", "S108"]
 "src/netmover/migrations/**" = ["E501"]
 
 [tool.mypy]