Netx tools: load from netx remote /mcp, add per-tool toggles

- Drop the TypeScript netx tool implementations and the hard-coded
  TOOLS_BY_GROUP list; register netx__* tools from the server's
  tools/list (group from _meta.netx.group) and forward tools/call.
- Thin Streamable HTTP client on standard fetch (fetchImpl injectable);
  cached catalog when netx is unreachable, refresh to reconnect.
- disabledTools (deny list; new server tools follow their group) and
  readOnlyOnly (only readOnlyHint=true tools), re-registered live.
- Settings card: per-group expandable tool rows with switches and a
  write marker; skills append a disabled-tools note.
- Toggles only control model visibility; netx enforces security.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

test/group-skills-disabled.test.mjs

@@ -0,0 +1,45 @@
+/**
+ * Skill injection appends disabled-tool footnotes when tools are filtered.
+ */
+
+import assert from 'node:assert/strict'
+import test from 'node:test'
+
+import { registerGroupSkills } from '../src/netx/group-skills.ts'
+
+test('registerGroupSkills appends disabled footnote; skips disabled groups', async () => {
+  /** @type {Array<{ name: string, content: string }>} */
+  const registered = []
+  const ctx = {
+    skills: {
+      register(skill) {
+        registered.push({ name: skill.name, content: skill.content })
+        return () => {}
+      },
+    },
+    logger: { warn() {} },
+  }
+
+  const dispose = await registerGroupSkills(ctx, ['ops'], 'test', {
+    disabledByGroup: { ops: ['netx__execManagedNe'] },
+    lang: 'zh',
+  })
+  assert.ok(registered.length >= 1)
+  assert.match(registered[0].content, /以下工具已禁用：netx__execManagedNe，不要调用/)
+  dispose()
+
+  registered.length = 0
+  const dispose2 = await registerGroupSkills(ctx, [], 'test', {
+    disabledByGroup: { ops: ['netx__execManagedNe'] },
+  })
+  assert.equal(registered.length, 0)
+  dispose2()
+
+  registered.length = 0
+  const dispose3 = await registerGroupSkills(ctx, ['ops'], 'test', {
+    disabledByGroup: { ops: ['netx__execManagedNe'] },
+    lang: 'en',
+  })
+  assert.match(registered[0].content, /The following tools are disabled: netx__execManagedNe/)
+  dispose3()
+})