feat(git): add stash push with optional paths and per-file scope

The stash push feature now supports limiting the stash to
selected files via an optional paths parameter.
The UI passes file paths to stash_push and adds a
per-file context menu for scoped stash operations.

- Extend stash API to accept optional paths for scoped stashes
- Implement per-file stash actions via a status panel context menu
- Update tests and docs to reflect scoped stash behavior

src/lib/components/StatusPanel.svelte

@@ -1,5 +1,6 @@
 <script lang="ts">
   import {
+    Archive,
     ArrowLeft,
     ArrowRight,
     FileDiff,
@@ -25,6 +26,7 @@
     onUnstage: (files: GitFileStatus[]) => void;
     onDiscard: (files: GitFileStatus[], staged: boolean) => void;
     onDiscardMany: (files: GitFileStatus[]) => void;
+    onStash: (files: GitFileStatus[], label: string) => void;
     onPatch: (file: GitFileStatus, staged: boolean) => void;
     onStageAll: () => void;
     onUnstageAll: () => void;
@@ -52,6 +54,13 @@
 
   type StatusTreeNode = StatusFolderNode | StatusFileNode;
 
+  interface StatusContextTarget {
+    lane: StatusLaneKind;
+    kind: "file" | "folder";
+    label: string;
+    files: GitFileStatus[];
+  }
+
   let {
     changedFiles = [],
     stagedCount = 0,
@@ -66,6 +75,7 @@
     onUnstage = () => {},
     onDiscard = () => {},
     onDiscardMany = () => {},
+    onStash = () => {},
     onPatch = () => {},
     onStageAll = () => {},
     onUnstageAll = () => {},
@@ -175,6 +185,9 @@
   let selectionAnchorKey = $state("");
   let statusView = $state<StatusViewMode>("list");
   let collapsedStatusFolders = $state<Set<string>>(new Set());
+  let statusContextTarget = $state<StatusContextTarget | null>(null);
+  let statusContextMenuX = $state(0);
+  let statusContextMenuY = $state(0);
 
   function toggleStatusFolder(lane: StatusLaneKind, path: string) {
     const next = new Set(collapsedStatusFolders);
@@ -184,6 +197,65 @@
     collapsedStatusFolders = next;
   }
 
+  function filesInStatusFolder(lane: StatusLaneKind, path: string): GitFileStatus[] {
+    const prefix = `${path.replace(/\\/g, "/").replace(/\/$/, "")}/`;
+    const files = lane === "unstaged" ? unstagedFiles : stagedFiles;
+    return files.filter((file) => {
+      const currentPath = file.path.replace(/\\/g, "/");
+      const oldPath = file.old_path?.replace(/\\/g, "/") ?? "";
+      return currentPath.startsWith(prefix) || oldPath.startsWith(prefix);
+    });
+  }
+
+  function openStatusContextMenu(
+    event: MouseEvent,
+    lane: StatusLaneKind,
+    kind: "file" | "folder",
+    label: string,
+    files: GitFileStatus[],
+  ) {
+    event.preventDefault();
+    event.stopPropagation();
+    if (files.length === 0) return;
+    statusContextMenuX = Math.max(8, Math.min(event.clientX, window.innerWidth - 288));
+    statusContextMenuY = Math.max(8, Math.min(event.clientY, window.innerHeight - 174));
+    statusContextTarget = { lane, kind, label, files };
+  }
+
+  function statusContextName(label: string): string {
+    const normalized = label.replace(/\\/g, "/").replace(/\/+$/, "");
+    return normalized.split("/").pop() || label;
+  }
+
+  function statusContextParent(label: string): string {
+    const normalized = label.replace(/\\/g, "/").replace(/\/+$/, "");
+    const separator = normalized.lastIndexOf("/");
+    return separator > 0 ? normalized.slice(0, separator) : "Repository root";
+  }
+
+  function closeStatusContextMenu() {
+    statusContextTarget = null;
+  }
+
+  function runStatusContextStageAction() {
+    const target = statusContextTarget;
+    if (!target) return;
+    closeStatusContextMenu();
+    if (target.lane === "unstaged") onStage(target.files);
+    else onUnstage(target.files);
+  }
+
+  function runStatusContextStashAction() {
+    const target = statusContextTarget;
+    if (!target) return;
+    closeStatusContextMenu();
+    onStash(target.files, target.label);
+  }
+
+  function handleStatusWindowKeydown(event: KeyboardEvent) {
+    if (event.key === "Escape") closeStatusContextMenu();
+  }
+
   function isStatusSelected(file: GitFileStatus): boolean {
     return selectedStatusPaths.has(fileKey(file));
   }
@@ -277,6 +349,8 @@
   });
 </script>
 
+<svelte:window onclick={closeStatusContextMenu} onkeydown={handleStatusWindowKeydown} />
+
 <section class="panel status-panel relative grid grid-rows-[auto_1fr] overflow-hidden" aria-label="Working tree status">
   <div class="section-head">
     <div>
@@ -336,7 +410,7 @@
         <div class="status-file-list">
           {#each visibleUnstagedRows as row (`unstaged:${row.kind}:${row.kind === "file" ? fileKey(row.file) : row.path}`)}
             {#if row.kind === "folder"}
-              <button class="status-folder-row" type="button" style={`--tree-indent: ${row.depth * 15}px`} onclick={() => toggleStatusFolder("unstaged", row.path)} title={row.path} aria-expanded={!collapsedStatusFolders.has(`unstaged:${row.path}`)}>
+              <button class="status-folder-row" type="button" style={`--tree-indent: ${row.depth * 15}px`} onclick={() => toggleStatusFolder("unstaged", row.path)} oncontextmenu={(event) => openStatusContextMenu(event, "unstaged", "folder", row.path, filesInStatusFolder("unstaged", row.path))} title={row.path} aria-expanded={!collapsedStatusFolders.has(`unstaged:${row.path}`)}>
                 <i class:expanded={!collapsedStatusFolders.has(`unstaged:${row.path}`)} class="status-tree-chevron" aria-hidden="true"></i>
                 {#if collapsedStatusFolders.has(`unstaged:${row.path}`)}<Folder class="status-folder-lucide" size={15} aria-hidden="true" />{:else}<FolderOpen class="status-folder-lucide" size={15} aria-hidden="true" />{/if}
                 <strong>{row.name}</strong>
@@ -345,7 +419,7 @@
             {:else}
               {@const file = row.file}
               {@const stageTargets = selectedStageTargets(file)}
-              <article class={`status-file-row${statusView === "tree" ? " status-tree-file" : ""}`} style={`--tree-indent: ${row.depth * 15}px`} class:selected={isStatusSelected(file)} class:active={selectedFilePath === file.path}>
+              <article class={`status-file-row${statusView === "tree" ? " status-tree-file" : ""}`} style={`--tree-indent: ${row.depth * 15}px`} class:selected={isStatusSelected(file)} class:active={selectedFilePath === file.path} oncontextmenu={(event) => openStatusContextMenu(event, "unstaged", "file", file.path, [file])}>
                 <button class="status-file-main" type="button" onclick={(event) => handleFileSelect(event, file)} title={`Select ${displayPath(file)} in Explorer`}>
                   <strong>{fileName(file)}</strong>
                   <span>{displayPath(file)}</span>
@@ -393,7 +467,7 @@
         <div class="status-file-list">
           {#each visibleStagedRows as row (`staged:${row.kind}:${row.kind === "file" ? fileKey(row.file) : row.path}`)}
             {#if row.kind === "folder"}
-              <button class="status-folder-row" type="button" style={`--tree-indent: ${row.depth * 15}px`} onclick={() => toggleStatusFolder("staged", row.path)} title={row.path} aria-expanded={!collapsedStatusFolders.has(`staged:${row.path}`)}>
+              <button class="status-folder-row" type="button" style={`--tree-indent: ${row.depth * 15}px`} onclick={() => toggleStatusFolder("staged", row.path)} oncontextmenu={(event) => openStatusContextMenu(event, "staged", "folder", row.path, filesInStatusFolder("staged", row.path))} title={row.path} aria-expanded={!collapsedStatusFolders.has(`staged:${row.path}`)}>
                 <i class:expanded={!collapsedStatusFolders.has(`staged:${row.path}`)} class="status-tree-chevron" aria-hidden="true"></i>
                 {#if collapsedStatusFolders.has(`staged:${row.path}`)}<Folder class="status-folder-lucide" size={15} aria-hidden="true" />{:else}<FolderOpen class="status-folder-lucide" size={15} aria-hidden="true" />{/if}
                 <strong>{row.name}</strong>
@@ -402,7 +476,7 @@
             {:else}
               {@const file = row.file}
               {@const unstageTargets = selectedUnstageTargets(file)}
-              <article class={`status-file-row${statusView === "tree" ? " status-tree-file" : ""}`} style={`--tree-indent: ${row.depth * 15}px`} class:selected={isStatusSelected(file)} class:active={selectedFilePath === file.path}>
+              <article class={`status-file-row${statusView === "tree" ? " status-tree-file" : ""}`} style={`--tree-indent: ${row.depth * 15}px`} class:selected={isStatusSelected(file)} class:active={selectedFilePath === file.path} oncontextmenu={(event) => openStatusContextMenu(event, "staged", "file", file.path, [file])}>
                 <button class="status-file-main" type="button" onclick={(event) => handleFileSelect(event, file)} title={`Select ${displayPath(file)} in Explorer`}>
                   <strong>{fileName(file)}</strong>
                   <span>{displayPath(file)}</span>
@@ -442,6 +516,40 @@
   {/if}
 </section>
 
+{#if statusContextTarget}
+  <div class="status-context-menu" style={`left: ${statusContextMenuX}px; top: ${statusContextMenuY}px;`} role="menu" tabindex="-1" aria-label={`Actions for ${statusContextTarget.label}`} onclick={(event) => event.stopPropagation()} onkeydown={(event) => { if (event.key === "Escape") closeStatusContextMenu(); event.stopPropagation(); }}>
+    <div class="status-context-label">
+      <span class="status-context-object-icon" aria-hidden="true">
+        {#if statusContextTarget.kind === "folder"}<FolderOpen size={16} />{:else}<FileDiff size={16} />{/if}
+      </span>
+      <span class="status-context-object-copy">
+        <span class="status-context-kind">{statusContextTarget.lane === "unstaged" ? "Unstaged" : "Staged"} {statusContextTarget.kind}</span>
+        <strong title={statusContextTarget.label}>{statusContextName(statusContextTarget.label)}</strong>
+        <span class="status-context-path" title={statusContextTarget.label}><Folder size={10} aria-hidden="true" />{statusContextParent(statusContextTarget.label)}</span>
+      </span>
+      <span class="status-context-count" title={`${statusContextTarget.files.length} ${statusContextTarget.files.length === 1 ? "file" : "files"}`}>
+        {statusContextTarget.files.length}
+      </span>
+    </div>
+    <button type="button" role="menuitem" onclick={runStatusContextStageAction} disabled={isBusy}>
+      <span class="status-context-action-icon" aria-hidden="true">
+        {#if statusContextTarget.lane === "unstaged"}<ArrowRight size={15} />{:else}<ArrowLeft size={15} />{/if}
+      </span>
+      <span class="status-context-action-copy">
+        <strong>{statusContextTarget.lane === "unstaged" ? "Stage" : "Unstage"} {statusContextTarget.kind}</strong>
+        <span>{statusContextTarget.lane === "unstaged" ? "Add to the next commit" : "Move back to working changes"}</span>
+      </span>
+    </button>
+    <button type="button" role="menuitem" onclick={runStatusContextStashAction} disabled={isBusy}>
+      <span class="status-context-action-icon" aria-hidden="true"><Archive size={15} /></span>
+      <span class="status-context-action-copy">
+        <strong>Stash {statusContextTarget.kind}</strong>
+        <span>Save {statusContextTarget.files.length === 1 ? "this file" : `${statusContextTarget.files.length} files`} for later</span>
+      </span>
+    </button>
+  </div>
+{/if}
+
 <style>
   .status-panel-overlay {
     position: absolute;