refactor(status): Support batch and all changes discard functionality

The file discarding mechanism has been significantly refactored to improve handling of multi-file operations. Instead of processing discards on a per-file basis, the system now supports batch actions for selected files or reverting all tracked modifications simultaneously. This update centralizes complex discard logic into dedicated functions across the component suite.

- Updated state management and types to handle arrays of file changes.
- Added UI elements and handlers for discarding all staged/unstaged changes.
- Enhanced the confirmation dialog to display multiple discarded targets in a list view.

src/App.svelte

@@ -133,7 +133,8 @@
   type AppView = "management" | "repository";
   type CredentialAction = "push" | "pull" | "fetch" | "clone";
   type PendingDiscard =
-    | { kind: "file"; file: GitFileStatus; staged: boolean }
+    | { kind: "file"; files: GitFileStatus[]; staged: boolean }
+    | { kind: "all-changes"; files: GitFileStatus[] }
     | { kind: "hunk"; file: GitFileStatus; staged: boolean; action: PatchApplyAction; patch: string };
 
   interface RepoTab {
@@ -2588,26 +2589,59 @@
     });
   }
 
-  function discardFile(file: GitFileStatus, staged: boolean) {
-    if (!activeRepoPath || isBusy) return;
-    pendingDiscard = { kind: "file", file, staged };
+  function discardFiles(files: GitFileStatus[], staged: boolean) {
+    if (!activeRepoPath || isBusy || files.length === 0) return;
+    pendingDiscard = { kind: "file", files, staged };
     trackEvent("discard_confirm_opened", {
       kind: "file",
       staged: staged ? 1 : 0,
+      files: files.length,
     });
   }
 
-  async function runDiscardFile(file: GitFileStatus, staged: boolean) {
-    await runOperation(`Discarding ${file.path}`, async () => {
-      applyStatus(await restoreFiles(activeRepoPath, [file.path], staged));
+  function discardChanges(files: GitFileStatus[]) {
+    if (!activeRepoPath || isBusy || files.length === 0) return;
+    pendingDiscard = { kind: "all-changes", files };
+    trackEvent("discard_confirm_opened", {
+      kind: "all",
+      files: files.length,
+    });
+  }
+
+  async function runDiscardFiles(files: GitFileStatus[], staged: boolean) {
+    if (files.length === 0) return;
+    const paths = files.map((file) => file.path);
+    await runOperation(files.length === 1 ? `Discarding ${baseName(files[0].path)}` : `Discarding ${files.length} files`, async () => {
+      applyStatus(await restoreFiles(activeRepoPath, paths, staged));
       await refreshExplorerFiles(activeRepoPath);
       await refreshFileHistory(activeRepoPath);
       trackEvent("file_discarded", {
+        files: files.length,
         staged: staged ? 1 : 0,
       });
     });
   }
 
+  // Discards both the staged and unstaged changes for each given file (used
+  // by "Discard all" and "Discard selected", which don't distinguish lanes).
+  async function runDiscardAllChanges(files: GitFileStatus[]) {
+    const stagedPaths = files.filter((file) => file.staged !== null).map((file) => file.path);
+    const unstagedPaths = files.filter((file) => file.unstaged !== null).map((file) => file.path);
+    if (stagedPaths.length === 0 && unstagedPaths.length === 0) return;
+    await runOperation(files.length === 1 ? `Discarding ${baseName(files[0].path)}` : `Discarding ${files.length} files`, async () => {
+      let nextStatus: GitStatus | null = null;
+      if (stagedPaths.length > 0) nextStatus = await restoreFiles(activeRepoPath, stagedPaths, true);
+      if (unstagedPaths.length > 0) nextStatus = await restoreFiles(activeRepoPath, unstagedPaths, false);
+      if (nextStatus) applyStatus(nextStatus);
+      await refreshExplorerFiles(activeRepoPath);
+      await refreshFileHistory(activeRepoPath);
+      trackEvent("file_discarded", {
+        files: files.length,
+        staged: 2,
+      });
+    });
+  }
+
   async function openLinePatch(file: GitFileStatus, staged: boolean) {
     if (!activeRepoPath) return;
     linePatchOpen = true;
@@ -2743,7 +2777,9 @@
     if (!discard || !activeRepoPath || isBusy) return;
 
     if (discard.kind === "file") {
-      await runDiscardFile(discard.file, discard.staged);
+      await runDiscardFiles(discard.files, discard.staged);
+    } else if (discard.kind === "all-changes") {
+      await runDiscardAllChanges(discard.files);
     } else {
       await runLinePatchAction(discard.action, discard.patch, discard.file, discard.staged);
     }
@@ -3750,7 +3786,8 @@
             onSelectFile={selectFileFromStatus}
             onStage={stageFile}
             onUnstage={unstageFile}
-            onDiscard={discardFile}
+            onDiscard={discardFiles}
+            onDiscardMany={discardChanges}
             onPatch={openLinePatch}
             onStageAll={stageAllFiles}
             onUnstageAll={unstageAllFiles}
@@ -3927,8 +3964,8 @@
 
 {#if pendingDiscard}
   <DiscardConfirmDialog
-    file={pendingDiscard.file}
-    staged={pendingDiscard.staged}
+    files={pendingDiscard.kind === "hunk" ? [pendingDiscard.file] : pendingDiscard.files}
+    staged={pendingDiscard.kind === "all-changes" ? null : pendingDiscard.staged}
     scope={pendingDiscard.kind === "hunk" ? "hunk" : "file"}
     {isBusy}
     onConfirm={confirmDiscard}