fix: tooltip reads 'Toggle Panel' and expand button aligns right

- Change title/aria-label on both collapse and expand buttons to 'Toggle Panel'
- Right-align the expand-panel-strip so the toggle icon sits on the right
  edge of the main column when the workspace panel is collapsed

src/client/src/components/PiWebApp.ts

@@ -1200,7 +1200,7 @@ export class PiWebApp extends LitElement {
         <aside>${this.isMobileNavigationLayout ? null : this.renderNavigationPanel(false)}</aside>
         <main class=${state.mainView === "chat" ? "chat-view" : state.mainView === "navigation" ? "navigation-view" : "workspace-view"}>
           ${this.renderContextBar()}
-          ${state.workspacePanelCollapsed ? html`<div class="expand-panel-strip"><button class="expand-workspace-panel-button" title="Expand workspace panel" aria-label="Expand workspace panel" @click=${() => { this.toggleWorkspacePanelCollapse(); }}><svg class="expand-icon" viewBox="0 0 24 24" aria-hidden="true" focusable="false"><path d="M15 18l-6-6 6-6"/></svg></button></div>` : null}
+          ${state.workspacePanelCollapsed ? html`<div class="expand-panel-strip"><button class="expand-workspace-panel-button" title="Toggle Panel" aria-label="Toggle Panel" @click=${() => { this.toggleWorkspacePanelCollapse(); }}><svg class="expand-icon" viewBox="0 0 24 24" aria-hidden="true" focusable="false"><path d="M15 18l-6-6 6-6"/></svg></button></div>` : null}
           <div class=${this.mobileTabsFrameClass()}>
             <div class="mobile-tabs" @scroll=${this.onMobileTabsScroll}>
               <button class=${state.mainView === "navigation" ? "mobile-navigation-tab selected" : "mobile-navigation-tab"} @click=${() => { this.selectMainView("navigation"); }}>Sessions</button>

src/client/src/components/WorkspacePanel.ts

@@ -71,7 +71,7 @@ export class WorkspacePanel extends LitElement {
                 ${visiblePanels.map((panel) => html`
                   <button class=${selectedPanel?.id === panel.id ? "selected" : ""} @click=${() => { this.onSelectTool(panel.id); }}>${this.renderPanelTitle(panel, context)}</button>
                 `)}
-                <button class="collapse-button" title="Collapse panel" aria-label="Collapse panel" @click=${() => { this.onToggleCollapse(); }}>${this.renderCollapseIcon()}</button>
+                <button class="collapse-button" title="Toggle Panel" aria-label="Toggle Panel" @click=${() => { this.onToggleCollapse(); }}>${this.renderCollapseIcon()}</button>
               </div>
             `}
             <small>${renderWorkspaceLabel(workspace.label, this.workspaceLabelItems, workspace.path)}</small>

src/client/src/components/shared.ts

@@ -95,7 +95,7 @@ export const appStyles = css`
   .mobile-navigation-tab, .mobile-navigation-panel { display: none; }
   .mobile-tabs button.selected { border-color: var(--pi-accent); background: var(--pi-selection-bg); }
   .tab-badge { display: inline-block; min-width: 14px; margin-left: 4px; border: 1px solid var(--pi-success-border); border-radius: 999px; background: var(--pi-success-surface); color: var(--pi-success); padding: 0 5px; font-size: 11px; line-height: 16px; text-align: center; }
-  .expand-panel-strip { flex: 0 0 auto; display: flex; align-items: center; padding: 4px 8px; border-bottom: 1px solid var(--pi-border-muted); }
+  .expand-panel-strip { flex: 0 0 auto; display: flex; align-items: center; justify-content: flex-end; padding: 4px 8px; border-bottom: 1px solid var(--pi-border-muted); }
   .expand-workspace-panel-button { display: inline-flex; align-items: center; justify-content: center; width: 30px; height: 30px; padding: 0; border-radius: 6px; }
   .expand-workspace-panel-button .expand-icon { width: 14px; height: 14px; fill: none; stroke: currentColor; stroke-width: 2; stroke-linecap: round; stroke-linejoin: round; pointer-events: none; }
   workspace-panel { min-width: 0; min-height: 0; border-left: 1px solid var(--pi-border); overflow: hidden; }