feat(ui): add collapsible Worktree and Tags panels to left sidebar

Add two new sidebar components (WorktreePanel, TagsPanel) and integrate them
into the compact left navigation layout:

- Wire up imports and rendering in App.svelte, including collapse toggles and
  resize handles for both panels. Persisted heights (localStorage) and keyboard
  resizing are supported; heights are clamped between 80 and 420px with a 140px
  default.
- Extend buildLeftSidebarRows and left-sidebar grid/template styles to include
  the new panels and reduce panel-handle thickness. Add extensive CSS for the
  compact accordion navigation, worktree and tags lists.
- Move tag and worktree management UI out of BranchPanel (remove tag props),
  and add dedicated handlers in App.svelte for the new panels.
- Refactor worktree loading: introduce a worktreeLoadId to guard async
  refreshWorktrees() calls and avoid race conditions. refreshWorktrees(path?)
  now takes an optional path and updates worktree state only when the request
  is still relevant.
- Small behavioral tweaks: stash panel default collapsed state changed to true
  and the explorer resize-handle visibility condition adjusted.

This commit only adds the UI/UX integration and local persistence for the new
panels and their resizing/refresh behavior.

src/lib/components/BranchPanel.svelte

@@ -1,7 +1,7 @@
 <script lang="ts">
-  import { Check, ChevronDown, ChevronRight, Folder, FolderOpen, GitBranch, GitCompare, GitMerge, HardDrive, Pencil, Plus, Tag as TagIcon, Trash2, Upload, X } from "@lucide/svelte";
+  import { Check, ChevronDown, ChevronRight, Folder, FolderOpen, GitBranch, GitCompare, GitMerge, HardDrive, Pencil, Plus, Trash2, X } from "@lucide/svelte";
   import { tick } from "svelte";
-  import type { GitBranch as GitBranchInfo, GitTag } from "../types";
+  import type { GitBranch as GitBranchInfo } from "../types";
 
   type BranchTreeNode = BranchFolderNode | BranchLeafNode;
 
@@ -48,7 +48,6 @@
     branches: GitBranchInfo[];
     localBranches: GitBranchInfo[];
     remoteBranches: GitBranchInfo[];
-    tags: GitTag[];
     hasRepository: boolean;
     isBusy: boolean;
     onCheckout: (branch: GitBranchInfo) => void;
@@ -60,10 +59,6 @@
     onDeleteBranch: (branch: GitBranchInfo) => void | Promise<void>;
     onDeleteRemoteBranch: (branch: GitBranchInfo) => void | Promise<void>;
     onDeleteBranchFolder: (folderName: string, branches: GitBranchInfo[], depth: number) => void | Promise<void>;
-    onCreateTag: (name: string, message: string) => void | Promise<void>;
-    onDeleteTag: (tag: GitTag) => void | Promise<void>;
-    onPushTag: (tag: GitTag) => void | Promise<void>;
-    onManageWorktrees: () => void;
     onCreateWorktree: (branch: GitBranchInfo) => void | Promise<void>;
     collapsed?: boolean;
     onToggleCollapsed?: () => void;
@@ -73,7 +68,6 @@
     branches = [],
     localBranches = [],
     remoteBranches = [],
-    tags = [],
     hasRepository = false,
     isBusy = false,
     onCheckout = () => {},
@@ -85,10 +79,6 @@
     onDeleteBranch = () => {},
     onDeleteRemoteBranch = () => {},
     onDeleteBranchFolder = () => {},
-    onCreateTag = () => {},
-    onDeleteTag = () => {},
-    onPushTag = () => {},
-    onManageWorktrees = () => {},
     onCreateWorktree = () => {},
     collapsed = false,
     onToggleCollapsed = () => {},
@@ -96,23 +86,14 @@
 
   let localOpen = $state(true);
   let remoteOpen = $state(false);
-  let tagsOpen = $state(false);
   let createOpen = $state(false);
   let newBranchName = $state("");
   let createInput = $state<HTMLInputElement | null>(null);
-  let tagCreateOpen = $state(false);
-  let newTagName = $state("");
-  let newTagMessage = $state("");
-  let tagCreateInput = $state<HTMLInputElement | null>(null);
   let contextBranch = $state<GitBranchInfo | null>(null);
   let contextFolder = $state<BranchFolderRow | null>(null);
   let branchContextMenuElement = $state<HTMLElement | null>(null);
   let contextMenuX = $state(0);
   let contextMenuY = $state(0);
-  let contextTag = $state<GitTag | null>(null);
-  let tagContextMenuElement = $state<HTMLElement | null>(null);
-  let tagContextMenuX = $state(0);
-  let tagContextMenuY = $state(0);
   let collapsedBranchFolders = $state<Set<string>>(new Set());
 
   let localBranchRows = $derived(buildBranchRows("local", localBranches, "local"));
@@ -227,6 +208,7 @@
 
   function openCreateForm() {
     if (!hasRepository || isBusy) return;
+    if (collapsed) onToggleCollapsed();
     createOpen = true;
     queueMicrotask(() => createInput?.focus());
   }
@@ -357,66 +339,8 @@
     await onRebase(branch);
   }
 
-  function openTagCreateForm() {
-    if (!hasRepository || isBusy) return;
-    tagCreateOpen = true;
-    queueMicrotask(() => tagCreateInput?.focus());
-  }
-
-  function closeTagCreateForm() {
-    tagCreateOpen = false;
-    newTagName = "";
-    newTagMessage = "";
-  }
-
-  async function submitCreateTag(event: SubmitEvent) {
-    event.preventDefault();
-    const name = newTagName.trim();
-    if (!name || !hasRepository || isBusy) return;
-    await onCreateTag(name, newTagMessage.trim());
-    newTagName = "";
-    newTagMessage = "";
-    tagCreateOpen = false;
-    tagsOpen = true;
-  }
-
-  async function openTagContextMenu(event: MouseEvent, tag: GitTag) {
-    event.preventDefault();
-    event.stopPropagation();
-    if (isBusy) return;
-
-    contextTag = tag;
-    tagContextMenuX = event.clientX + 2;
-    tagContextMenuY = event.clientY + 2;
-    await tick();
-    if (contextTag !== tag) return;
-
-    const position = fitContextMenuToViewport(tagContextMenuElement, event.clientX, event.clientY);
-    tagContextMenuX = position.x;
-    tagContextMenuY = position.y;
-  }
-
-  function closeTagContextMenu() {
-    contextTag = null;
-  }
-
-  async function pushContextTag() {
-    const tag = contextTag;
-    if (!tag || isBusy) return;
-    closeTagContextMenu();
-    await onPushTag(tag);
-  }
-
-  async function deleteContextTag() {
-    const tag = contextTag;
-    if (!tag || isBusy) return;
-    closeTagContextMenu();
-    await onDeleteTag(tag);
-  }
-
   function closeAllContextMenus() {
     closeBranchContextMenu();
-    closeTagContextMenu();
   }
 
   function handleWindowKeydown(event: KeyboardEvent) {
@@ -428,10 +352,7 @@
 
 <section class="panel branch-panel grid grid-rows-[auto_1fr] overflow-hidden" class:collapsed aria-label="Branches">
   <div class="section-head">
-    <div>
-      <span class="eyebrow">Branches</span>
-      <h2 class="mt-0.5 text-ink text-base font-bold leading-tight">Refs</h2>
-    </div>
+    <h2 class="sidebar-section-title"><GitBranch size={16} aria-hidden="true" />Branches</h2>
     <div class="branch-head-actions">
       <button
         class="branch-create-toggle"
@@ -543,7 +464,6 @@
                     <GitBranch size={16} aria-hidden="true" />
                     <div>
                       <strong>{row.displayName}</strong>
-                      <span>{row.scopeLabel}</span>
                     </div>
                   </div>
                   {#if row.branch.current}
@@ -611,7 +531,6 @@
                     <GitBranch size={16} aria-hidden="true" />
                     <div>
                       <strong>{row.displayName}</strong>
-                      <span>{row.scopeLabel}</span>
                     </div>
                   </div>
                   {#if row.branch.current}
@@ -624,100 +543,9 @@
         {/if}
       </div>
 
-      <div class="branch-group">
-        <div class="tag-group-head">
-          <button
-            class="branch-group-toggle"
-            type="button"
-            onclick={() => { tagsOpen = !tagsOpen; }}
-            aria-expanded={tagsOpen}
-          >
-            {#if tagsOpen}
-              <ChevronDown size={14} aria-hidden="true" />
-            {:else}
-              <ChevronRight size={14} aria-hidden="true" />
-            {/if}
-            <span>Tags</span>
-            <span class="branch-group-count">{tags.length}</span>
-          </button>
-          <button
-            class="branch-create-toggle"
-            type="button"
-            onclick={openTagCreateForm}
-            disabled={!hasRepository || isBusy}
-            title="Create new tag"
-            aria-label="Create new tag"
-          >
-            <Plus size={13} aria-hidden="true" />
-          </button>
-        </div>
 
-        {#if tagCreateOpen}
-          <form class="branch-create-form tag-create-form" onsubmit={submitCreateTag}>
-            <TagIcon size={15} aria-hidden="true" />
-            <input
-              bind:this={tagCreateInput}
-              bind:value={newTagName}
-              disabled={isBusy}
-              autocomplete="off"
-              spellcheck="false"
-              placeholder="v1.0.0"
-              aria-label="New tag name"
-            />
-            <input
-              bind:value={newTagMessage}
-              disabled={isBusy}
-              autocomplete="off"
-              spellcheck="false"
-              placeholder="Message (optional)"
-              aria-label="Tag message"
-            />
-            <button class="branch-create-action confirm" type="submit" disabled={isBusy || newTagName.trim().length === 0} title="Create tag">
-              <Check size={14} aria-hidden="true" />
-            </button>
-            <button class="branch-create-action" type="button" onclick={closeTagCreateForm} disabled={isBusy} title="Cancel">
-              <X size={14} aria-hidden="true" />
-            </button>
-          </form>
-        {/if}
 
-        {#if tagsOpen}
-          {#if tags.length === 0}
-            <div class="branch-empty">No tags.</div>
-          {:else}
-            {#each tags as tag (tag.name)}
-              <article
-                class="branch-row"
-                oncontextmenu={(event) => openTagContextMenu(event, tag)}
-                title={tag.message ?? tag.name}
-              >
-                <div class="branch-info">
-                  <TagIcon size={16} aria-hidden="true" />
-                  <div>
-                    <strong>{tag.name}</strong>
-                    <span>{tag.short_hash}</span>
-                  </div>
-                </div>
-              </article>
-            {/each}
-          {/if}
-        {/if}
-      </div>
 
-      <div class="branch-group">
-        <button
-          class="branch-group-toggle worktree-group-toggle"
-          type="button"
-          onclick={onManageWorktrees}
-          disabled={isBusy}
-          aria-haspopup="dialog"
-          title="Manage repository worktrees"
-        >
-          <HardDrive size={14} aria-hidden="true" />
-          <span>Worktrees</span>
-          <span class="branch-group-count">Manage</span>
-        </button>
-      </div>
     </div>
   {/if}
 
@@ -792,24 +620,4 @@
     </div>
   {/if}
 
-  {#if contextTag}
-    <div
-      bind:this={tagContextMenuElement}
-      class="branch-context-menu"
-      style={`left: ${tagContextMenuX}px; top: ${tagContextMenuY}px;`}
-      role="menu"
-      tabindex="-1"
-      aria-label={`Actions for ${contextTag.name}`}
-    >
-      <button type="button" role="menuitem" onclick={pushContextTag} disabled={isBusy}>
-        <Upload size={14} aria-hidden="true" />
-        Push to remote
-      </button>
-      <div class="menu-separator" role="separator"></div>
-      <button class="danger" type="button" role="menuitem" onclick={deleteContextTag} disabled={isBusy} title="Delete local tag">
-        <Trash2 size={14} aria-hidden="true" />
-        Delete
-      </button>
-    </div>
-  {/if}
 </section>