feat(ai): enable all image models with server-side tier enforcement

convex/ai.ts

@@ -416,6 +416,12 @@ export const generateImage = action({
       throw new Error(`Unknown model: ${modelId}`);
     }
 
+    const subscription = await ctx.runQuery(api.credits.getSubscription, {});
+    const userTier = normalizePublicTier(subscription?.tier);
+    if (!isImageModelAllowedForTier(modelConfig.minTier, userTier)) {
+      throw new Error(`Model ${modelId} requires ${modelConfig.minTier} tier`);
+    }
+
     await ctx.runMutation(internal.credits.checkAbuseLimits, {});
 
     let usageIncremented = false;
@@ -506,6 +512,14 @@ function isVideoModelAllowedForTier(modelTier: "free" | "starter" | "pro", userT
   return tierOrder[userTier] >= tierOrder[modelTier];
 }
 
+function isImageModelAllowedForTier(
+  minTier: "free" | "starter" | "pro" | "max",
+  userTier: "free" | "starter" | "pro" | "max"
+) {
+  const tierOrder = { free: 0, starter: 1, pro: 2, max: 3 } as const;
+  return tierOrder[userTier] >= tierOrder[minTier];
+}
+
 export const setVideoTaskInfo = internalMutation({
   args: {
     nodeId: v.id("nodes"),

convex/openrouter.ts

@@ -9,10 +9,9 @@ export interface OpenRouterModel {
   estimatedCostPerImage: number; // in Euro-Cent (for credit reservation)
   /** Gleiche Einheit wie UI „Cr“ / lib/ai-models creditCost */
   creditCost: number;
+  minTier: "free" | "starter" | "pro" | "max";
 }
 
-// Phase 1: Gemini 2.5 Flash Image only.
-// Add more models here in Phase 2 when the model selector UI is built.
 export const IMAGE_MODELS: Record<string, OpenRouterModel> = {
   "google/gemini-2.5-flash-image": {
     id: "google/gemini-2.5-flash-image",
@@ -20,6 +19,71 @@ export const IMAGE_MODELS: Record<string, OpenRouterModel> = {
     tier: "standard",
     estimatedCostPerImage: 4, // ~€0.04 in Euro-Cent
     creditCost: 4,
+    minTier: "free",
+  },
+  "black-forest-labs/flux.2-klein-4b": {
+    id: "black-forest-labs/flux.2-klein-4b",
+    name: "FLUX.2 Klein 4B",
+    tier: "budget",
+    estimatedCostPerImage: 2,
+    creditCost: 2,
+    minTier: "free",
+  },
+  "bytedance-seed/seedream-4.5": {
+    id: "bytedance-seed/seedream-4.5",
+    name: "Seedream 4.5",
+    tier: "standard",
+    estimatedCostPerImage: 5,
+    creditCost: 5,
+    minTier: "free",
+  },
+  "google/gemini-3.1-flash-image-preview": {
+    id: "google/gemini-3.1-flash-image-preview",
+    name: "Gemini 3.1 Flash Image",
+    tier: "standard",
+    estimatedCostPerImage: 6,
+    creditCost: 6,
+    minTier: "free",
+  },
+  "openai/gpt-5-image-mini": {
+    id: "openai/gpt-5-image-mini",
+    name: "GPT-5 Image Mini",
+    tier: "premium",
+    estimatedCostPerImage: 8,
+    creditCost: 8,
+    minTier: "starter",
+  },
+  "sourceful/riverflow-v2-fast": {
+    id: "sourceful/riverflow-v2-fast",
+    name: "Riverflow V2 Fast",
+    tier: "premium",
+    estimatedCostPerImage: 9,
+    creditCost: 9,
+    minTier: "starter",
+  },
+  "sourceful/riverflow-v2-pro": {
+    id: "sourceful/riverflow-v2-pro",
+    name: "Riverflow V2 Pro",
+    tier: "premium",
+    estimatedCostPerImage: 12,
+    creditCost: 12,
+    minTier: "starter",
+  },
+  "google/gemini-3-pro-image-preview": {
+    id: "google/gemini-3-pro-image-preview",
+    name: "Gemini 3 Pro Image",
+    tier: "premium",
+    estimatedCostPerImage: 13,
+    creditCost: 13,
+    minTier: "starter",
+  },
+  "openai/gpt-5-image": {
+    id: "openai/gpt-5-image",
+    name: "GPT-5 Image",
+    tier: "premium",
+    estimatedCostPerImage: 15,
+    creditCost: 15,
+    minTier: "starter",
   },
 };
 

tests/lib/ai-models.test.ts

@@ -6,6 +6,7 @@ import {
   getAvailableImageModels,
   getModel,
 } from "@/lib/ai-models";
+import { IMAGE_MODELS as OPENROUTER_MODELS } from "@/convex/openrouter";
 
 describe("ai image models registry", () => {
   it("contains all 9 PRD models in stable order", () => {
@@ -32,4 +33,12 @@ describe("ai image models registry", () => {
   it("resolves model lookup", () => {
     expect(getModel(DEFAULT_MODEL_ID)?.creditCost).toBeGreaterThan(0);
   });
+
+  it("keeps frontend and backend image model ids and credit costs in sync", () => {
+    expect(Object.keys(OPENROUTER_MODELS)).toEqual(IMAGE_MODELS.map((model) => model.id));
+
+    for (const model of IMAGE_MODELS) {
+      expect(OPENROUTER_MODELS[model.id]?.creditCost).toBe(model.creditCost);
+    }
+  });
 });