refactor(shell): retire the plugin's own right panel and free windows

DSH 0.1.5 owns the right column (its native Sidebar hosts every tab type
this plugin registers), so the plugin's own right panel, its width drag /
new-session seed prefs, and the free-window feature are gone. The bottom
workbench is the only plugin-owned surface left, and its expand/collapse
control is registered into DSH's session-header utilities list slot (the
header's corner seat belongs to the native sidebar's own control).

- state: one `bottomSplits` tree; `makeDefaultState()` takes no arguments;
  `toggleBottomPanel` / `openTabInBottomPane` are the only landing
  reducers; `setBottomHeight` and `sanitizeState` share the
  `CONVERSATION_MIN` cap (a persisted tall height no longer snaps on the
  first drag).
- service: every landing in the workbench (creation or focus) expands it;
  `SIDEBAR_FEATURES` drops `'floatWindows'`; the open/close/activate tab
  pools cover the single tree.
- shell: `Sidebar.tsx` renders only the bottom workbench; the toggle lives
  in `sidebar/bottom-toggle.tsx`; layout-push pushes height only (no width,
  no `--dsh-sidebar-width`).
- prefs: `openByDefault` / `defaultWidthPercent` / `changesDiffFloat`
  removed from the schema, defaults, client parser, settings page, and all
  20 dictionaries; the retired keys in stored documents are ignored.
- tests: free-window specs deleted, panel/float assertions dropped,
  remaining suites adapted (124 files / 1287 tests); the mount lane asserts
  the header toggle and sweeps the native sidebar's guide page.
- docs: README / README_EN / guide §0,§11 / AGENTS test map.

src/client/SideCardSection.tsx

@@ -54,11 +54,8 @@ import clsx from 'clsx'
 import type {} from '@deepseek-ai/dsh-client-ui-settings/client'
 import type { PropsRuntime } from '@deepseek-ai/dsh-client-ui-slots'
 import {
-  clampWidthPercent,
   TITLE_BAR_STRIP_MAX,
   TITLE_BAR_STRIP_MIN,
-  WIDTH_PERCENT_MAX,
-  WIDTH_PERCENT_MIN,
   type SidebarPrefs,
 } from '../prefs-shared.ts'
 import { api } from './api.ts'
@@ -572,7 +569,6 @@ export function SettingsBody(props: {
  */
 export function SideCardSection({ store, service }: SideCardSectionProps) {
   const [prefs, setPrefs] = useState<SidebarPrefs>(() => store.getPrefs())
-  const [widthDraft, setWidthDraft] = useState<string>(String(store.getPrefs().defaultWidthPercent))
   const [error, setError] = useState<string | null>(null)
   // Which feature's secondary settings popup is open (null = closed).
   const [settingsFor, setSettingsFor] = useState<TabDescriptor | FileViewerDescriptor | null>(null)
@@ -624,9 +620,7 @@ export function SideCardSection({ store, service }: SideCardSectionProps) {
       if (cancelled) return
       revisionRef.current = view.revision
       if (dirtyRef.current) return
-      const next = parsePrefs(view.value)
-      setPrefs(next)
-      setWidthDraft(String(next.defaultWidthPercent))
+      setPrefs(parsePrefs(view.value))
     }).catch(() => { /* the store's defaults stay authoritative */ })
     return () => { cancelled = true }
   }, [])
@@ -657,9 +651,7 @@ export function SideCardSection({ store, service }: SideCardSectionProps) {
 
   /** Settle one commit: success adopts the server values, failure reverts. */
   const applyOutcome = (previous: SidebarPrefs, outcome: { ok: boolean; prefs: SidebarPrefs }): void => {
-    const settled = outcome.ok ? outcome.prefs : previous
-    setPrefs(settled)
-    setWidthDraft(String(settled.defaultWidthPercent))
+    setPrefs(outcome.ok ? outcome.prefs : previous)
   }
 
   /** Optimistically apply one pref patch, then commit (revert on failure). */
@@ -672,10 +664,6 @@ export function SideCardSection({ store, service }: SideCardSectionProps) {
     void commit(patch).then(outcome => applyOutcome(previous, outcome))
   }
 
-  const onToggle = (next: boolean): void => {
-    applyPref({ openByDefault: next })
-  }
-
   /** Flip one per-tab enable switch (merge into the tabsEnabled map). */
   const onToggleTab = (id: string, next: boolean): void => {
     applyPref({ tabsEnabled: { ...optimisticRef.current.tabsEnabled, [id]: next } })
@@ -778,20 +766,6 @@ export function SideCardSection({ store, service }: SideCardSectionProps) {
     return raw
   }
 
-  const commitWidth = (): void => {
-    const parsed = Number(widthDraft)
-    if (!Number.isFinite(parsed)) {
-      setWidthDraft(String(prefs.defaultWidthPercent))
-      return
-    }
-    const clamped = clampWidthPercent(parsed)
-    const previous = prefs
-    setPrefs({ ...previous, defaultWidthPercent: clamped })
-    setWidthDraft(String(clamped))
-    setError(null)
-    void commit({ defaultWidthPercent: clamped }).then(outcome => applyOutcome(previous, outcome))
-  }
-
   /**
    * One SMALL toggle card for the responsive inventory grid: the card's main
    * area is the switch (click to flips, visual state IS the state), the icon
@@ -867,40 +841,6 @@ export function SideCardSection({ store, service }: SideCardSectionProps) {
       {/* 常规: the DSH settings-row recipe — title/desc left, control right. */}
       <div className={css.group}>
         <div className={css.groupHeading}>{t('settingsGeneralTitle')}</div>
-        <div className={css.row}>
-          <span className={css.rowText}>
-            <span className={css.title}>{t('settingsOpenTitle')}</span>
-            <span className={css.desc}>{t('settingsOpenDesc')}</span>
-          </span>
-          <Switch
-            label={t('settingsOpenTitle')}
-            checked={prefs.openByDefault}
-            onChange={onToggle}
-          />
-        </div>
-        <div className={css.row}>
-          <span className={css.rowText}>
-            <span className={css.title}>{t('settingsWidthTitle')}</span>
-            <span className={css.desc}>{t('settingsWidthDesc')}</span>
-          </span>
-          <span className={css.control}>
-            <Input
-              type="number"
-              className={css.percentInput}
-              value={widthDraft}
-              min={WIDTH_PERCENT_MIN}
-              max={WIDTH_PERCENT_MAX}
-              step={1}
-              aria-label={t('settingsWidthTitle')}
-              onChange={event => { setWidthDraft(event.currentTarget.value) }}
-              onBlur={commitWidth}
-              onKeyDown={event => {
-                if (event.key === 'Enter') event.currentTarget.blur()
-              }}
-            />
-            <span className={css.suffix}>{t('settingsWidthSuffix')}</span>
-          </span>
-        </div>
         <div className={css.row}>
           <span className={css.rowText}>
             <span className={css.title}>{t('settingsOpenToolsTitle')}</span>