feat: 终端二级设置支持自定义字体（字体族 + 9–32px 字号，实时生效）

- SidebarPrefs 新增 terminalFontFamily（空 = 跟随主题等宽字体）/ terminalFontSize（9–32，默认 13），PrefsSchema 与 parsePrefs 同步校验
- 声明式设置 API 扩展：SidebarSettingToggle 支持 type: 'switch' | 'text' | 'number'（缺省 switch，向后兼容）+ min/max/placeholder/unit
- 终端卡片齿轮弹窗新增「终端字体」「终端字号」两行：blur/Enter 提交、number 钳制、提交失败回滚草稿
- TerminalView 经 store 订阅实时应用字体（options + re-fit + resize），懒加载 chunk 无新增依赖
- 新增 resolveTerminalFont 纯函数（回退链：用户字体 → 主题 token → 内置等宽栈）并单测
- 版本 0.11.0，README/AGENTS.md/设计文档同步

src/prefs-shared.ts

@@ -33,6 +33,18 @@ export interface SidebarPrefs {
    * user explicitly enables it in the side card settings.
    */
   agentTerminalTools: boolean
+  /**
+   * Custom terminal font-family stack (a CSS font-family value, e.g.
+   * `'JetBrains Mono', monospace`). Empty string follows the app's theme
+   * monospace font (`--ds-font-family-code`). Applied live to every
+   * terminal tab; configured under the terminal card's secondary settings.
+   */
+  terminalFontFamily: string
+  /**
+   * Custom terminal font size in px (9–32). Applied live to every terminal
+   * tab; configured under the terminal card's secondary settings.
+   */
+  terminalFontSize: number
   /**
    * Whether expanding the bottom panel for the FIRST time in a session tries
    * to open a fresh terminal tab there (the terminal quota/type still gates
@@ -104,6 +116,11 @@ export const WIDTH_PERCENT_MIN = 20
 export const WIDTH_PERCENT_MAX = 60
 export const WIDTH_PERCENT_DEFAULT = 30
 
+/** Range contract of {@link SidebarPrefs.terminalFontSize}. */
+export const TERMINAL_FONT_SIZE_MIN = 9
+export const TERMINAL_FONT_SIZE_MAX = 32
+export const TERMINAL_FONT_SIZE_DEFAULT = 13
+
 /** Fallback prefs used whenever the settings document is unreachable or malformed. */
 export const SIDEBAR_PREFS_DEFAULTS: SidebarPrefs = {
   openByDefault: true,
@@ -112,6 +129,8 @@ export const SIDEBAR_PREFS_DEFAULTS: SidebarPrefs = {
   autoOpenJobs: true,
   agentTerminalTools: false,
   bottomPanelAutoTerminal: true,
+  terminalFontFamily: '',
+  terminalFontSize: TERMINAL_FONT_SIZE_DEFAULT,
   interceptOpenPath: true,
   htmlViewerNoSandbox: false,
   htmlViewerDefaultUnsafe: false,
@@ -125,3 +144,8 @@ export const SIDEBAR_PREFS_DEFAULTS: SidebarPrefs = {
 export function clampWidthPercent(value: number): number {
   return Math.min(WIDTH_PERCENT_MAX, Math.max(WIDTH_PERCENT_MIN, Math.round(value)))
 }
+
+/** Clamp one terminal font size into the contract range (shared by schema and client reads). */
+export function clampTerminalFontSize(value: number): number {
+  return Math.min(TERMINAL_FONT_SIZE_MAX, Math.max(TERMINAL_FONT_SIZE_MIN, Math.round(value)))
+}