fix(settings): use the host's @deepseek-ai/schemastery so volatile prefs apply

Every side-card switch was dead: settings.update returned OK and
cordis.patch.yml was written, yet the running plugin never saw the new value
and nothing reported an error.

Root cause: the plugin declared Config with the plain npm `schemastery`
(3.18.0), which has no volatile support. The host resolves plugin config via
`runtime.Config['~standard'].validate()` — i.e. the plugin's OWN schemastery —
so `meta.volatile` nodes were never wrapped in cosmokit volatile references.
`cordis-plugin-loader`'s `_commitVolatile()` bails out as soon as
`volatileEntries(fiber.config)` is empty, so every volatile-only edit was
silently dropped: no in-place update, no plugin restart.

Fix: import z from '@deepseek-ai/schemastery' (peer provided by the host at
mount; pinned 3.18.4 as a devDependency for the dev tree), matching the
repo's existing pnpm-workspace convention for @deepseek-ai/* peers.

Verified: probe reports tabsIsVolatile=true and revision climbing 0->6 across
six writes, each read-back matching the written value (previously the value
was frozen and revision stuck at 1).

Also in this change:
- apes tab ids lose their colon (apes:tasks -> apesTasks, ...): the host's
  settings projection dropped map keys containing a colon.
- sidebar prefs ns follows the profile entry id (`better-sidebar`).
- subagent rows degrade to summary rows when the root catalog never hydrates.
- docs/feedback-0.2.0-rc2-contract-gaps.md: four host contract gaps, gap 4
  documenting the silent volatile-write drop above.

Gates: typecheck 0, lint 0, build 0, test 131 files / 1385 passed.

src/config.ts

@@ -5,7 +5,7 @@
  * @module dsh-apes-sidebar/config
  */
 
-import z from 'schemastery'
+import z from '@deepseek-ai/schemastery'
 import {
   TERMINAL_FONT_SIZE_DEFAULT,
   TERMINAL_FONT_SIZE_MAX,
@@ -28,8 +28,20 @@ export {
   type SidebarPrefs,
 } from './prefs-shared.ts'
 
-/** Tunable sidebar host limits (every field optional; defaults fill in). */
-export interface SidebarConfig {
+/**
+ * Tunable sidebar host limits (every field optional; defaults fill in).
+ *
+ * Since 0.2.0-rc.2 the loader auto-registers the plugin's `Config` schema
+ * under ns = package name, and the settings service's `update()` only accepts
+ * patches to fields marked `volatile`. The user-facing side-card preferences
+ * (formerly the dead `PrefsSchema` export) are therefore MERGED into this
+ * schema with `extra('volatile', true)` so the settings routes can persist
+ * them. The deployment fields above (readLimit/shell/…) are deliberately
+ * NON-volatile: they are set from `cordis.patch.yml` / profile config, not
+ * from the user's settings page, and must not be writable through
+ * `settings.update`.
+ */
+export interface SidebarConfig extends Partial<SidebarPrefs> {
   /** Read cap of one text file (bytes); larger files return truncated. */
   readLimit?: number
   /** Media route cap (bytes); larger binaries are refused. */
@@ -60,8 +72,9 @@ export interface SidebarConfig {
   shellArgs?: string[]
 }
 
-/** Schemastery schema for the plugin configuration. */
+/** Schemastery schema for the plugin configuration (deployment + user prefs). */
 export const Config: z<SidebarConfig> = z.object({
+  // ── Deployment fields (NON-volatile; set from cordis.patch.yml / profile) ──
   readLimit: z.number().step(1).min(1).default(512 * 1024),
   mediaLimit: z.number().step(1).min(1).default(20 * 1024 * 1024),
   uploadLimit: z.number().step(1).min(1).default(128 * 1024 * 1024),
@@ -70,6 +83,47 @@ export const Config: z<SidebarConfig> = z.object({
   reconnectGraceMs: z.number().step(1).min(0).default(30_000),
   shell: z.string().default(''),
   shellArgs: z.array(z.string()).default([]),
+  // ── User-facing side-card preferences (volatile; writable via settings.update) ──
+  // 0.2.0-rc.2: the settings service's `update()` only accepts patches to fields
+  // whose schema node (or an ancestor) is marked `volatile`. Every user-editable
+  // preference below is tagged `extra('volatile', true)` so the /sidebar/settings
+  // routes can persist them. These were formerly the dead `PrefsSchema` export;
+  // merging them into `Config` (the schema the loader actually registers) is what
+  // makes the settings page switches stick instead of 400 → optimistic rollback.
+  autoOpenSubagent: z.boolean().default(true).extra('volatile', true),
+  autoOpenJobs: z.boolean().default(true).extra('volatile', true),
+  agentTerminalTools: z.boolean().default(false).extra('volatile', true),
+  agentOpenTools: z.boolean().default(false).extra('volatile', true),
+  bottomPanelAutoTerminal: z.boolean().default(true).extra('volatile', true),
+  terminalFontFamily: z.string().default('').extra('volatile', true),
+  terminalFontSize: z.number().step(1).min(TERMINAL_FONT_SIZE_MIN).max(TERMINAL_FONT_SIZE_MAX).default(TERMINAL_FONT_SIZE_DEFAULT).extra('volatile', true),
+  editorExplorer: z.boolean().default(false).extra('volatile', true),
+  workspaceFence: z.boolean().default(true).extra('volatile', true),
+  terminalShell: z.string().default('').extra('volatile', true),
+  terminalShellArgs: z.string().default('').extra('volatile', true),
+  titleBarScheme: z.union([z.const('auto'), z.const('web'), z.const('preset'), z.const('custom')]).extra('volatile', true),
+  titleBarPresetId: z.string().extra('volatile', true),
+  customCss: z.string().extra('volatile', true),
+  titleBarCompat: z.boolean().default(false).extra('volatile', true),
+  titleBarStripPx: z.number().step(1).min(TITLE_BAR_STRIP_MIN).max(TITLE_BAR_STRIP_MAX).default(TITLE_BAR_STRIP_DEFAULT).extra('volatile', true),
+  htmlViewerNoSandbox: z.boolean().default(false).extra('volatile', true),
+  htmlViewerDefaultUnsafe: z.boolean().default(false).extra('volatile', true),
+  browserNoSandbox: z.boolean().default(false).extra('volatile', true),
+  browserInterceptLinks: z.boolean().default(true).extra('volatile', true),
+  browserInterceptHttp: z.boolean().default(true).extra('volatile', true),
+  browserInterceptHttps: z.boolean().default(false).extra('volatile', true),
+  browserAllowedLoopback: z.string().default('').extra('volatile', true),
+  // Per-feature enable switches are OPEN maps (any tab/viewer id, built-in or
+  // external): an absent key means enabled, so old documents resolve to {}
+  // (everything on) with no migration. Non-boolean values fail validation.
+  // The whole dict node is volatile, so any key beneath it is writable.
+  tabsEnabled: z.dict(z.boolean()).default({}).extra('volatile', true),
+  viewersEnabled: z.dict(z.boolean()).default({}).extra('volatile', true),
+  // Plugin-owned settings blobs (v0.12.0+) are an OPEN nested map: any
+  // descriptor id may carry any JSON-serializable values. This is the
+  // "settings seam" opening — without it the seam would drop third-party
+  // keys as unknown schema fields.
+  pluginSettings: z.dict(z.dict(z.any())).default({}).extra('volatile', true),
 })
 
 /** Fully defaulted sidebar host settings. */