Fix the dead win7 context menu, flatten the selection, add a tab menu

Right-click did nothing under the win7 skin, and then swallowed the next
click. 7.css declares `position: relative` on ul[role=menu] and the `skin`
layer outranks `utilities`, so Tailwind's `.fixed` lost: [style.left/top.px]
became flow offsets from the menu's static position — the last child of the
h-screen frame — and every menu rendered below the viewport, unreachable
behind overflow:hidden. Its backdrop is a plain <div>, unmatched by 7.css, so
that stayed genuinely fixed and ate the following click. Regressed in 0ae2a62,
when the menu adopted 7.css's real markup.

Restated `position: fixed` in skinfix, scoped to a new `w7-ctx` marker so
7.css's own menus keep theirs. scripts/menu-probe.ts is the regression test:
it renders the menu at declared coordinates, pixel-scans whether it landed
there, and carries a marker-less control menu (the bug verbatim) as its own
discriminator. A resting pixel diff cannot see this class of bug.

Selection band goes flat: --w7-sel-bg/-bd (#cbe8f6/#26a0da) is what Explorer
actually painted, where 7.css reused --w7-el-grad-h, its Aero element-hover
ramp. That var is left alone — buttons and tabs still want the gloss. The
unfocused pane gets the grey idle band; the band still never disappears with
focus, it only weakens. Harness diff confirms the change touches selection
rows and nothing else, in both themes.

New workspace-tab right-click menu in both skins: New Tab, Close Tab, Close
Other Tabs, Close Tabs to the Right, Disconnect. The target id travels inside
the action string because the right-clicked tab is not necessarily the active
one. Illegal entries are disabled rather than omitted, the way Win7 greyed
out — and since 7.css's [aria-disabled] handling is CSS-only, the keyboard
paths check the flag themselves.

Co-Authored-By: Claude <noreply@anthropic.com>

ui/src/app/core/context-menu.service.ts

@@ -1,7 +1,7 @@
 import { Injectable, inject, signal } from '@angular/core';
 import type { ColumnKey, EntryType } from '@shared/types';
 import { I18nService } from './i18n.service';
-import { IS_MAC, IS_WINDOWS } from './platform';
+import { IS_MAC, IS_WINDOWS, MOD_LABEL } from './platform';
 import { RpcService } from './rpc.service';
 
 /** Optional list columns, in display order (Name is fixed). */
@@ -10,12 +10,15 @@ const COLUMN_KEYS: ColumnKey[] = ['size', 'mtime', 'kind', 'rights', 'owner', 'g
 export interface MenuItem {
   type?: 'separator';
   label?: string;
-  /** Emitted verbatim to the action dispatcher (`ctx-*` / `col:*`). */
+  /** Emitted verbatim to the action dispatcher (`ctx-*` / `col:*` / `tab:*`). */
   action?: string;
   checked?: boolean;
   tooltip?: string;
   /** Shortcut hint, rendered right-aligned. */
   accelerator?: string;
+  /** Greyed and unclickable. Win7 menus disable rather than hide, so the set
+   *  of commands stays in the same place from one right-click to the next. */
+  disabled?: boolean;
 }
 
 export interface MenuRequest {
@@ -24,6 +27,16 @@ export interface MenuRequest {
   items: MenuItem[];
 }
 
+export interface TabMenuContext {
+  /** The right-clicked tab (NOT necessarily the active one). */
+  id: number;
+  /** Position in the strip, for "close to the right". */
+  index: number;
+  tabCount: number;
+  /** Any pane in this tab holds a live remote session. */
+  isRemote: boolean;
+}
+
 export interface RowMenuContext {
   path: string;
   name: string;
@@ -114,6 +127,45 @@ export class ContextMenuService {
     return items;
   }
 
+  /**
+   * The workspace-tab menu. Actions carry the target tab's id, because the
+   * right-clicked tab is not necessarily the active one — nothing here may
+   * assume `activeWorkspace`.
+   *
+   * Everything illegal is DISABLED, not omitted: a menu whose items move
+   * between right-clicks is a Win7 sin, and "Close Tab" greyed out explains
+   * why the last tab cannot be closed better than its absence does.
+   *
+   * Duplicate/Rename/Save-session are deliberately absent until tabs have an
+   * identity to duplicate (a stored connection id) — the sessions round.
+   */
+  tabItems(ctx: TabMenuContext): MenuItem[] {
+    const t = (key: string) => this.i18n.t(key);
+    const last = ctx.tabCount <= 1;
+    return [
+      { label: t('ctx.tabNew'), action: 'tab:new', accelerator: `${MOD_LABEL}T` },
+      { type: 'separator' },
+      {
+        label: t('ctx.tabClose'),
+        action: `tab:close:${ctx.id}`,
+        accelerator: `${MOD_LABEL}W`,
+        disabled: last,
+      },
+      { label: t('ctx.tabCloseOthers'), action: `tab:close-others:${ctx.id}`, disabled: last },
+      {
+        label: t('ctx.tabCloseRight'),
+        action: `tab:close-right:${ctx.id}`,
+        disabled: ctx.index >= ctx.tabCount - 1,
+      },
+      { type: 'separator' },
+      {
+        label: t('ctx.tabDisconnect'),
+        action: `tab:disconnect:${ctx.id}`,
+        disabled: !ctx.isRemote,
+      },
+    ];
+  }
+
   /** Column picker for the list headers: checkable toggles per column. */
   columnItems(visible: ColumnKey[]): MenuItem[] {
     return COLUMN_KEYS.map((key) => ({