feat: Add playlist management functionality and compliance checks

- Introduced a new "Playlists" column in results view with visual indicators for membership.
- Added `playlist_api.py` to handle playlist-related operations (fetch, add, remove tracks).
- Implemented `PlaylistManagerDialog` for seamless playlist addition/removal with caching.
- Integrated compliance check script (`check_agents_compliance.py`) for ensuring coding standards.
- Added extensive documentation (`playlist_membership_manager.md`) covering architecture and flow.
- Updated GUI logic and QStandardItemModel setup to include playlist data.
- Included unit tests for playlist management components and API.

2 files changed, 262 insertions, 0 deletions

diff --git a/tidal_dl_ng/ui/dialog_playlist_manager.py b/tidal_dl_ng/ui/dialog_playlist_manager.py
new file mode 100644
index 0000000..17327f6
--- /dev/null
+++ b/tidal_dl_ng/ui/dialog_playlist_manager.py
@@ -0,0 +1,115 @@
+################################################################################
+## Form generated from reading UI file 'dialog_playlist_manager.ui'
+##
+## Created by: Qt User Interface Compiler version 6.10.0
+##
+## WARNING! All changes made in this file will be lost when recompiling UI file!
+################################################################################
+
+from PySide6.QtCore import QCoreApplication, QMetaObject, QRect, QSize, Qt
+from PySide6.QtWidgets import (
+    QFrame,
+    QHBoxLayout,
+    QLabel,
+    QPushButton,
+    QScrollArea,
+    QSizePolicy,
+    QSpacerItem,
+    QVBoxLayout,
+    QWidget,
+)
+
+
+class Ui_DialogPlaylistManager:
+    def setupUi(self, DialogPlaylistManager):
+        if not DialogPlaylistManager.objectName():
+            DialogPlaylistManager.setObjectName("DialogPlaylistManager")
+        DialogPlaylistManager.resize(609, 760)
+        DialogPlaylistManager.setMinimumSize(QSize(520, 560))
+        self.verticalLayoutRoot = QVBoxLayout(DialogPlaylistManager)
+        self.verticalLayoutRoot.setObjectName("verticalLayoutRoot")
+        self.horizontalLayoutHeader = QHBoxLayout()
+        self.horizontalLayoutHeader.setObjectName("horizontalLayoutHeader")
+        self.labelTitle = QLabel(DialogPlaylistManager)
+        self.labelTitle.setObjectName("labelTitle")
+        self.labelTitle.setWordWrap(True)
+
+        self.horizontalLayoutHeader.addWidget(self.labelTitle)
+
+        self.verticalLayoutRoot.addLayout(self.horizontalLayoutHeader)
+
+        self.frameSeparator = QFrame(DialogPlaylistManager)
+        self.frameSeparator.setObjectName("frameSeparator")
+        self.frameSeparator.setFrameShape(QFrame.Shape.HLine)
+        self.frameSeparator.setFrameShadow(QFrame.Shadow.Sunken)
+
+        self.verticalLayoutRoot.addWidget(self.frameSeparator)
+
+        self.scrollArea = QScrollArea(DialogPlaylistManager)
+        self.scrollArea.setObjectName("scrollArea")
+        self.scrollArea.setWidgetResizable(True)
+        self.scrollAreaWidgetContents = QWidget()
+        self.scrollAreaWidgetContents.setObjectName("scrollAreaWidgetContents")
+        self.scrollAreaWidgetContents.setGeometry(QRect(0, 0, 589, 666))
+        self.verticalLayoutList = QVBoxLayout(self.scrollAreaWidgetContents)
+        self.verticalLayoutList.setObjectName("verticalLayoutList")
+        self.labelEmpty = QLabel(self.scrollAreaWidgetContents)
+        self.labelEmpty.setObjectName("labelEmpty")
+        self.labelEmpty.setAlignment(Qt.AlignmentFlag.AlignCenter)
+
+        self.verticalLayoutList.addWidget(self.labelEmpty)
+
+        self.verticalSpacer = QSpacerItem(20, 40, QSizePolicy.Policy.Minimum, QSizePolicy.Policy.Expanding)
+
+        self.verticalLayoutList.addItem(self.verticalSpacer)
+
+        self.scrollArea.setWidget(self.scrollAreaWidgetContents)
+
+        self.verticalLayoutRoot.addWidget(self.scrollArea)
+
+        self.frameFooterSeparator = QFrame(DialogPlaylistManager)
+        self.frameFooterSeparator.setObjectName("frameFooterSeparator")
+        self.frameFooterSeparator.setFrameShape(QFrame.Shape.HLine)
+        self.frameFooterSeparator.setFrameShadow(QFrame.Shadow.Sunken)
+
+        self.verticalLayoutRoot.addWidget(self.frameFooterSeparator)
+
+        self.horizontalLayoutFooter = QHBoxLayout()
+        self.horizontalLayoutFooter.setObjectName("horizontalLayoutFooter")
+        self.horizontalSpacer = QSpacerItem(40, 20, QSizePolicy.Policy.Expanding, QSizePolicy.Policy.Minimum)
+
+        self.horizontalLayoutFooter.addItem(self.horizontalSpacer)
+
+        self.buttonClose = QPushButton(DialogPlaylistManager)
+        self.buttonClose.setObjectName("buttonClose")
+
+        self.horizontalLayoutFooter.addWidget(self.buttonClose)
+
+        self.verticalLayoutRoot.addLayout(self.horizontalLayoutFooter)
+
+        self.retranslateUi(DialogPlaylistManager)
+        self.buttonClose.clicked.connect(DialogPlaylistManager.accept)
+
+        self.buttonClose.setDefault(True)
+
+        QMetaObject.connectSlotsByName(DialogPlaylistManager)
+
+    # setupUi
+
+    def retranslateUi(self, DialogPlaylistManager):
+        DialogPlaylistManager.setWindowTitle(
+            QCoreApplication.translate("DialogPlaylistManager", "G\u00e9rer les playlists", None)
+        )
+        self.labelTitle.setText(
+            QCoreApplication.translate(
+                "DialogPlaylistManager",
+                'G\u00e9rer les playlists pour : <b><span style="color:#1e88e5;">Titre de la Piste</span></b>',
+                None,
+            )
+        )
+        self.labelEmpty.setText(
+            QCoreApplication.translate("DialogPlaylistManager", "Aucune playlist disponible.", None)
+        )
+        self.buttonClose.setText(QCoreApplication.translate("DialogPlaylistManager", "Fermer", None))
+
+    # retranslateUi
diff --git a/tidal_dl_ng/ui/dialog_playlist_manager.ui b/tidal_dl_ng/ui/dialog_playlist_manager.ui
new file mode 100644
index 0000000..5f7b831
--- /dev/null
+++ b/tidal_dl_ng/ui/dialog_playlist_manager.ui
@@ -0,0 +1,147 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>DialogPlaylistManager</class>
+ <widget class="QDialog" name="DialogPlaylistManager">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>609</width>
+    <height>760</height>
+   </rect>
+  </property>
+  <property name="minimumSize">
+   <size>
+    <width>520</width>
+    <height>560</height>
+   </size>
+  </property>
+  <property name="windowTitle">
+   <string>Gérer les playlists</string>
+  </property>
+  <layout class="QVBoxLayout" name="verticalLayoutRoot">
+   <item>
+    <layout class="QHBoxLayout" name="horizontalLayoutHeader">
+     <item>
+      <widget class="QLabel" name="labelTitle">
+       <property name="text">
+        <string>Gérer les playlists pour : &lt;b&gt;&lt;span style=&quot;color:#1e88e5;&quot;&gt;Titre de la Piste&lt;/span&gt;&lt;/b&gt;</string>
+       </property>
+       <property name="wordWrap">
+        <bool>true</bool>
+       </property>
+      </widget>
+     </item>
+    </layout>
+   </item>
+   <item>
+    <widget class="QFrame" name="frameSeparator">
+     <property name="frameShape">
+      <enum>QFrame::Shape::HLine</enum>
+     </property>
+     <property name="frameShadow">
+      <enum>QFrame::Shadow::Sunken</enum>
+     </property>
+    </widget>
+   </item>
+   <item>
+    <widget class="QScrollArea" name="scrollArea">
+     <property name="widgetResizable">
+      <bool>true</bool>
+     </property>
+     <widget class="QWidget" name="scrollAreaWidgetContents">
+      <property name="geometry">
+       <rect>
+        <x>0</x>
+        <y>0</y>
+        <width>589</width>
+        <height>666</height>
+       </rect>
+      </property>
+      <layout class="QVBoxLayout" name="verticalLayoutList">
+       <item>
+        <widget class="QLabel" name="labelEmpty">
+         <property name="text">
+          <string>Aucune playlist disponible.</string>
+         </property>
+         <property name="alignment">
+          <set>Qt::AlignmentFlag::AlignCenter</set>
+         </property>
+        </widget>
+       </item>
+       <item>
+        <spacer name="verticalSpacer">
+         <property name="orientation">
+          <enum>Qt::Orientation::Vertical</enum>
+         </property>
+         <property name="sizeHint" stdset="0">
+          <size>
+           <width>20</width>
+           <height>40</height>
+          </size>
+         </property>
+        </spacer>
+       </item>
+      </layout>
+     </widget>
+    </widget>
+   </item>
+   <item>
+    <widget class="QFrame" name="frameFooterSeparator">
+     <property name="frameShape">
+      <enum>QFrame::Shape::HLine</enum>
+     </property>
+     <property name="frameShadow">
+      <enum>QFrame::Shadow::Sunken</enum>
+     </property>
+    </widget>
+   </item>
+   <item>
+    <layout class="QHBoxLayout" name="horizontalLayoutFooter">
+     <item>
+      <spacer name="horizontalSpacer">
+       <property name="orientation">
+        <enum>Qt::Orientation::Horizontal</enum>
+       </property>
+       <property name="sizeHint" stdset="0">
+        <size>
+         <width>40</width>
+         <height>20</height>
+        </size>
+       </property>
+      </spacer>
+     </item>
+     <item>
+      <widget class="QPushButton" name="buttonClose">
+       <property name="text">
+        <string>Fermer</string>
+       </property>
+       <property name="default">
+        <bool>true</bool>
+       </property>
+      </widget>
+     </item>
+    </layout>
+   </item>
+  </layout>
+ </widget>
+ <resources/>
+ <connections>
+  <connection>
+   <sender>buttonClose</sender>
+   <signal>clicked()</signal>
+   <receiver>DialogPlaylistManager</receiver>
+   <slot>accept()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>20</x>
+     <y>20</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>20</x>
+     <y>20</y>
+    </hint>
+   </hints>
+  </connection>
+ </connections>
+</ui>