fix(agent-presets,web): broken presets are roster rows, not gaps

A hand-damaged preset was silent until the worst moment. An unparsable
composition listed as an ordinary selectable row and failed only at the
next session start — set as default, every new session failed. A
directory whose composition file was deleted vanished from the roster
while still occupying its id: copy answered "delete the existing preset
first" while remove answered "not found", a dead end.

Discovery now owns health: every id-shaped directory is a roster slot,
broken when its composition is missing or unloadable, checked with the
loader's own entryListSchema dialect (!!js included) so health never
rejects what the loader accepts. `broken` rides AgentPreset, the
agentPreset.list entry, and the UI row; mount/recompose/standingKeyFor
refuse broken up front with the discovery-reported reason, while
resolve/read/remove still answer. The section renders marked red cards —
unselectable, uncopyable, deletable, location kept on custom rows — and
both pickers drop broken rows entirely.

The cordis preset's persona now forbids editing the shipped install
(corrupting cordis would disable the mode itself) and points authoring
at $DSH_HOME/.agent-presets; its skill teaches preset.yml metadata, the
copy-first workflow, the one-escalation sandbox reality, and honest
verification. Exercised live: asked to edit the shipped composition the
composed agent refuses citing both rules; asked for real presets (simple
and complex) it lands them under the user root with one approved
escalation each and self-checks with the loader dialect.

packages/client/ui-agent-preset/tests/section.spec.tsx

@@ -172,6 +172,43 @@ describe('the preset list', () => {
     expect(duplicate.getAttribute('data-tip')).toBe(en.duplicateUnavailable)
   })
 
+  it('marks a broken custom preset: unselectable, uncopyable, still deletable', () => {
+    const actions = renderSection({
+      rows: [
+        { id: 'standard', trust: 'system', isDefault: true },
+        { id: 'ghost', trust: 'user', isDefault: false, name: '幽灵预设', broken: 'the composition file agent.cordis.yml is missing' },
+      ],
+    })
+
+    const ghost = rowFor('ghost')
+    // The reason is on the card, and the body cannot pick what cannot mount.
+    expect(within(ghost).getByText(en.brokenBadge)).toBeTruthy()
+    expect(within(ghost).getByRole('alert').textContent).toContain('is missing')
+    const body = within(ghost).getByRole('button', { name: `${en.brokenBadge}: 幽灵预设` })
+    expect(body).toHaveProperty('disabled', true)
+    fireEvent.click(body)
+    expect(actions.makeDefault).not.toHaveBeenCalled()
+    // Copying a broken preset would only mint another broken one; deleting
+    // and the location remain — the files are where it gets fixed.
+    const duplicate = within(ghost).getByRole('button', { name: `${en.duplicate}: 幽灵预设` })
+    expect(duplicate).toHaveProperty('disabled', true)
+    expect(duplicate.getAttribute('data-tip')).toBe(en.brokenNoCopy)
+    expect(within(ghost).getByRole('button', { name: `${en.delete}: 幽灵预设` })).toBeTruthy()
+    expect(within(ghost).getByRole('button', { name: `${en.openLocation}: 幽灵预设` })).toBeTruthy()
+  })
+
+  it('withholds the viewer on a broken shipped preset', () => {
+    renderSection({
+      rows: [{ id: 'standard', trust: 'system', isDefault: false, name: '标准模式', broken: 'the composition is not valid YAML' }],
+    })
+
+    // There is no readable composition to offer; the reason on the card is
+    // the whole story a shipped row can tell.
+    const standard = rowFor('standard')
+    expect(within(standard).queryByRole('button', { name: `${en.view}: 标准模式` })).toBeNull()
+    expect(within(standard).getByRole('alert').textContent).toContain('not valid YAML')
+  })
+
   it('labels the location by what it will do without a desktop', () => {
     renderSection({ hasDocument: false })
 

packages/client/ui-agent-preset/tests/settings-store.spec.ts

@@ -90,6 +90,20 @@ describe('the agent-preset settings controller', () => {
     ])
   })
 
+  it('offers no broken preset: the pickers choose the NEXT session\'s composition', async () => {
+    const controller = new AgentPresetSettingsController(fakeApi([
+      { id: 'standard', trust: 'system', isDefault: true },
+      { id: 'damaged', trust: 'user', isDefault: false, broken: 'the composition is not valid YAML' },
+    ] as never))
+
+    await controller.load()
+
+    // A broken preset cannot compose a session; listing it here would defer
+    // that discovery to a failed session start. The management section shows
+    // (and deletes) it from its own store instead.
+    expect(controller.store.getSnapshot().options.map(option => option.id)).toEqual(['standard'])
+  })
+
   it('carries the display metadata a preset published', async () => {
     const controller = new AgentPresetSettingsController(fakeApi([
       { id: 'standard', trust: 'system', isDefault: true, name: '标准模式', description: '完整的编码 agent。' },