chore(sponsors): drop AICoding partner from README, presets and i18n

Remove AICoding (aicoding.sh) sponsor entry from the three README files
and the provider preset across all seven app_types (claude, codex,
gemini, hermes, opencode, openclaw, claudeDesktop). Also drop the
matching partner_promotion.aicoding string in zh/en/ja locales.

The icon (src/icons/extracted/index.ts) and the legacy provider id in
codex_history_migration.rs are kept intentionally: the former for
possible later re-use, the latter so existing users' Codex history
still gets bucketed into "custom" on upgrade.

src/config/codexProviderPresets.ts

@@ -945,22 +945,6 @@ requires_openai_auth = true`,
     icon: "aicodemirror",
     iconColor: "#000000",
   },
-  {
-    name: "AICoding",
-    websiteUrl: "https://aicoding.sh",
-    apiKeyUrl: "https://aicoding.sh/i/CCSWITCH",
-    auth: generateThirdPartyAuth(""),
-    config: generateThirdPartyConfig(
-      "aicoding",
-      "https://api.aicoding.sh",
-      "gpt-5.4",
-    ),
-    endpointCandidates: ["https://api.aicoding.sh"],
-    isPartner: true,
-    partnerPromotionKey: "aicoding",
-    icon: "aicoding",
-    iconColor: "#000000",
-  },
   {
     name: "CrazyRouter",
     websiteUrl: "https://www.crazyrouter.com",