feat(Notepad): Complete refactor - New popout mode & settings

- Add a full popout Notepad experience w/new layout settings
- New ability to choose the left or right side of the screen
- Add more safegaurds to preserve user data throughout
- New banner to show file reload/conflict handling
- New extensionless file support
- Polish settings with gap controls, compact buttons, and shortcuts help

quickshell/Services/NotepadStorageService.qml

@@ -23,6 +23,49 @@ Singleton {
     property var tabsBeingCreated: ({})
     property bool metadataLoaded: false
 
+    // Shared live edit state across slideout and popout surfaces.
+    property var sessionBuffers: ({})
+    property int sessionBufferRevision: 0
+
+    function setSessionBuffer(tabId, content, baseline) {
+        if (tabId === undefined || tabId === null || tabId < 0)
+            return
+        var next = Object.assign({}, sessionBuffers)
+        if (content !== baseline) {
+            next[tabId] = { content: content, baseline: baseline }
+        } else {
+            delete next[tabId]
+        }
+        sessionBuffers = next
+        sessionBufferRevision++
+    }
+
+    function getSessionBuffer(tabId) {
+        return sessionBuffers[tabId]
+    }
+
+    function clearSessionBuffer(tabId) {
+        if (sessionBuffers[tabId] === undefined)
+            return
+        var next = Object.assign({}, sessionBuffers)
+        delete next[tabId]
+        sessionBuffers = next
+        sessionBufferRevision++
+    }
+
+    property var conflictTabId: -1
+    property string conflictDiskContent: ""
+
+    function flagConflict(tabId, diskContent) {
+        conflictDiskContent = diskContent
+        conflictTabId = tabId
+    }
+
+    function clearConflict() {
+        conflictTabId = -1
+        conflictDiskContent = ""
+    }
+
     Component.onCompleted: {
         ensureDirectories()
     }
@@ -209,6 +252,10 @@ Singleton {
         if (tabIndex < 0 || tabIndex >= tabs.length) return
 
         var newTabs = tabs.slice()
+        var closedTabId = newTabs[tabIndex] ? newTabs[tabIndex].id : -1
+        clearSessionBuffer(closedTabId)
+        if (conflictTabId === closedTabId)
+            clearConflict()
 
         if (newTabs.length <= 1) {
             var id = Date.now()