feat(web): token 数以 K 输入显示,已存凭证显示掩码占位(FIX-8)

- 新增 UnitInput 与 kind=tokens:上下文预算、单次 token 上限、自定义模型上下文窗口以 K 输入(允许小数),存储仍为原始 token 数;校验与提示用 K 表述;列表/详情 token 数统一 K/M 简写(formatTokens)
- 新增 SecretInput 与 kind=secret:已保存时显示「已设置 ••••••••」(有服务端掩码时带末 4 位),聚焦直接输入替换,留空保持,「清除」确认后保存生效;替换模型服务、TMDB、网页搜索、下载器、媒体服务器、浏览器服务、站点账号、Passkey、本机 Token 各处
- 统一只写凭证服务端语义:省略或空串 = 不变,null = 清除(contracts secretInput);下载器/媒体服务器新增清除;站点凭证同类更新可留空保持密码/Cookie/API Key/TOTP,TOTP 可 null 清除,不再误删 TOTP 与 UA
- contextBudget 最小值 4096→4000、contextWindow 1024→1000,便于按 K 填写
- 测试:换算与校验、SecretInput 渲染与状态、各接口留空不变/显式清除

Co-Authored-By: Claude Opus 5.5 <[email protected]>

apps/web/app/components/sites/site-dialogs.tsx

@@ -28,7 +28,13 @@ import { Input } from "~/components/ui/input.tsx";
 import { Switch } from "~/components/ui/switch.tsx";
 import { errorMessage } from "~/lib/api.ts";
 import { cn } from "~/lib/utils.ts";
-import { CredentialFields, credentialBody, emptyCredential } from "./credential-fields.tsx";
+import {
+  CredentialFields,
+  credentialBody,
+  draftFromAccount,
+  emptyCredential,
+  type SavedCredential,
+} from "./credential-fields.tsx";
 import {
   AUTH_KIND_LABEL,
   bytes,
@@ -229,7 +235,11 @@ export function CredentialDialog({
     (current && current.authKind !== "passkey" && kinds.includes(current.authKind as LoginKind)
       ? (current.authKind as LoginKind)
       : (kinds[0] ?? "cookie"));
-  const [draft, setDraft] = useState(() => emptyCredential(initialKind));
+  const [draft, setDraft] = useState(() => draftFromAccount(initialKind, current));
+  const saved: SavedCredential | null =
+    current && current.authKind !== "passkey" && current.secretRef
+      ? { kind: current.authKind as LoginKind, hasTotp: current.hasTotp }
+      : null;
   const [errors, setErrors] = useState<Record<string, string>>({});
   const [result, setResult] = useState<SiteLoginResult | null>(null);
   const put = usePutCredentials();
@@ -239,7 +249,7 @@ export function CredentialDialog({
 
   const submit = async (e: React.FormEvent) => {
     e.preventDefault();
-    const b = credentialBody(draft, current?.label ?? site.key);
+    const b = credentialBody(draft, current?.label ?? site.key, saved);
     if (!b.body) {
       setErrors(b.errors);
       return;
@@ -283,6 +293,7 @@ export function CredentialDialog({
             errors={errors}
             disabled={busy}
             idPrefix="upd"
+            saved={saved}
           />
         </form>
         {result && !result.ok ? (