fix: add projectId warning logs and blackbox.ai provider (#175, #176)

- Added warning logs when generateProjectId() is used as fallback
  in antigravity.ts and openai-to-gemini.ts (3 locations), helping
  admins diagnose 404 errors from fake GCP project IDs (#176)
- Added blackbox.ai as new OpenAI-compatible provider with 6 models
  (GPT-4o, Gemini 2.5 Flash, Claude Sonnet 4, DeepSeek V3,
  Blackbox AI, Blackbox AI Pro) and provider logo (#175)

open-sse/config/providerRegistry.ts

@@ -641,6 +641,25 @@ export const REGISTRY: Record<string, RegistryEntry> = {
     ],
   },
 
+  blackbox: {
+    id: "blackbox",
+    alias: "bb",
+    format: "openai",
+    executor: "default",
+    baseUrl: "https://api.blackbox.ai/v1/chat/completions",
+    modelsUrl: "https://api.blackbox.ai/v1/models",
+    authType: "apikey",
+    authHeader: "bearer",
+    models: [
+      { id: "gpt-4o", name: "GPT-4o" },
+      { id: "gemini-2.5-flash", name: "Gemini 2.5 Flash" },
+      { id: "claude-sonnet-4", name: "Claude Sonnet 4" },
+      { id: "deepseek-v3", name: "DeepSeek V3" },
+      { id: "blackboxai", name: "Blackbox AI" },
+      { id: "blackboxai-pro", name: "Blackbox AI Pro" },
+    ],
+  },
+
   xai: {
     id: "xai",
     alias: "xai",

open-sse/executors/antigravity.ts

@@ -36,8 +36,17 @@ export class AntigravityExecutor extends BaseExecutor {
   }
 
   transformRequest(model, body, stream, credentials) {
+    const hasRealProject = !!credentials?.projectId;
     const projectId = credentials?.projectId || this.generateProjectId();
 
+    if (!hasRealProject) {
+      console.warn(
+        `[Antigravity] ⚠️ No projectId in credentials — using generated fallback "${projectId}". ` +
+          `This may cause 404 errors if the account has no active GCP project. ` +
+          `Ensure the OAuth token includes a valid project.`
+      );
+    }
+
     // Fix contents for Claude models via Antigravity
     const normalizedContents =
       body.request?.contents?.map((c) => {

open-sse/translator/request/openai-to-gemini.ts

@@ -271,8 +271,16 @@ export function openaiToGeminiCLIRequest(model, body, stream) {
 
 // Wrap Gemini CLI format in Cloud Code wrapper
 function wrapInCloudCodeEnvelope(model, geminiCLI, credentials = null, isAntigravity = false) {
+  const hasRealProject = !!credentials?.projectId;
   const projectId = credentials?.projectId || generateProjectId();
 
+  if (!hasRealProject) {
+    console.warn(
+      `[${isAntigravity ? "Antigravity" : "GeminiCLI"}] ⚠️ No projectId in credentials — using generated fallback "${projectId}". ` +
+        `This may cause 404 errors. Ensure the OAuth token includes a valid GCP project.`
+    );
+  }
+
   const cleanModel = model.includes("/") ? model.split("/").pop()! : model;
 
   const envelope: Record<string, any> = {
@@ -315,10 +323,17 @@ function wrapInCloudCodeEnvelope(model, geminiCLI, credentials = null, isAntigra
   return envelope;
 }
 
-// Wrap Claude format in Cloud Code envelope for Antigravity
 function wrapInCloudCodeEnvelopeForClaude(model, claudeRequest, credentials = null) {
+  const hasRealProject = !!credentials?.projectId;
   const projectId = credentials?.projectId || generateProjectId();
 
+  if (!hasRealProject) {
+    console.warn(
+      `[Antigravity/Claude] ⚠️ No projectId in credentials — using generated fallback "${projectId}". ` +
+        `This may cause 404 errors. Ensure the OAuth token includes a valid GCP project.`
+    );
+  }
+
   const cleanModel = model.includes("/") ? model.split("/").pop()! : model;
 
   const envelope: Record<string, any> = {