feat(providers): rebrand CTok to ETok across presets, icons, and docs

The vendor renamed its domain, API endpoints, and trademark from CTok to
ETok. Update all user-facing branding accordingly:

- Presets (claude, claude-desktop, codex, gemini, hermes, openclaw,
  opencode): ctok.ai -> etok.ai, api.ctok.ai -> api.etok.ai, internal
  provider id ctok -> etok, display name CTok.ai -> ETok.ai
- Icons: replace inline placeholder SVG with the new ETok brand PNG,
  moved from `icons` to `iconUrls`; key ctok -> etok; banner logo
  ctok.png -> etok.png
- README (en/zh/ja/de) partner banner: new logo, links, and copy
- i18n (en/ja/zh/zh-TW): partnerPromotion key ctok -> etok

Keep "ctok" in the Codex history-migration whitelist as a legacy id and
add "etok", so existing users' local session history stays correctly
bucketed after the rename.

src/config/codexProviderPresets.ts

@@ -1222,20 +1222,20 @@ requires_openai_auth = true`,
     iconColor: "#000000",
   },
   {
-    name: "CTok.ai",
-    websiteUrl: "https://ctok.ai",
-    apiKeyUrl: "https://ctok.ai",
+    name: "ETok.ai",
+    websiteUrl: "https://etok.ai",
+    apiKeyUrl: "https://etok.ai",
     auth: generateThirdPartyAuth(""),
     config: generateThirdPartyConfig(
-      "ctok",
-      "https://api.ctok.ai/v1",
+      "etok",
+      "https://api.etok.ai/v1",
       "gpt-5.5",
     ),
-    endpointCandidates: ["https://api.ctok.ai/v1"],
+    endpointCandidates: ["https://api.etok.ai/v1"],
     category: "third_party",
     isPartner: true, // 合作伙伴
-    partnerPromotionKey: "ctok", // 促销信息 i18n key
-    icon: "ctok",
+    partnerPromotionKey: "etok", // 促销信息 i18n key
+    icon: "etok",
     iconColor: "#000000",
   },
   {