chore: remove MVP positioning and align plan defaults (#15)

## Summary
- remove MVP wording from repository docs and guidance
- rename the system plan document and update references to it
- align the default subscription plan code/name with product wording
- document hard subscription expiry with no grace period

## Verification
- docker build -f infra/docker/web.Dockerfile .
- docker build -f infra/docker/migrate.Dockerfile .

Co-authored-by: sirily <sirily@git.shararam.party>
Reviewed-on: #15

packages/db/README.md

@@ -4,7 +4,7 @@ Database package for `nproxy`.
 
 ## Implemented in this iteration
 - Prisma package scaffold
-- Initial Prisma schema for MVP persisted state
+- Current Prisma schema for persisted state
 - Shared schema path export for runtime tooling
 
 ## Current scope

packages/db/src/auth-store.ts

@@ -73,7 +73,7 @@ export function createPrismaAuthStore(database: PrismaClient = defaultPrisma) {
       return database.$transaction(async (transaction) => {
         const defaultPlan = await transaction.subscriptionPlan.findFirst({
           where: {
-            code: "mvp_monthly",
+            code: "monthly",
             isActive: true,
           },
         });

packages/db/src/bootstrap.ts

@@ -10,8 +10,8 @@ export interface SubscriptionPlanSeedInput {
 }
 
 export const defaultSubscriptionPlanSeed: SubscriptionPlanSeedInput = {
-  code: "mvp_monthly",
-  displayName: "MVP Monthly",
+  code: "monthly",
+  displayName: "Monthly",
   monthlyRequestLimit: 100,
   monthlyPriceUsd: 9.99,
   billingCurrency: "USDT",
@@ -21,6 +21,8 @@ export async function ensureSubscriptionPlan(
   input: SubscriptionPlanSeedInput,
   database: PrismaClient = defaultPrisma,
 ): Promise<void> {
+  await reconcileDefaultSubscriptionPlan(input, database);
+
   await database.subscriptionPlan.upsert({
     where: {
       code: input.code,
@@ -48,3 +50,47 @@ export async function ensureDefaultSubscriptionPlan(
 ): Promise<void> {
   await ensureSubscriptionPlan(defaultSubscriptionPlanSeed, database);
 }
+
+async function reconcileDefaultSubscriptionPlan(
+  input: SubscriptionPlanSeedInput,
+  database: PrismaClient,
+): Promise<void> {
+  const existing = await database.subscriptionPlan.findUnique({
+    where: {
+      code: input.code,
+    },
+    select: {
+      id: true,
+    },
+  });
+
+  if (existing) {
+    return;
+  }
+
+  const candidate = await database.subscriptionPlan.findFirst({
+    where: {
+      monthlyRequestLimit: input.monthlyRequestLimit,
+      monthlyPriceUsd: new Prisma.Decimal(input.monthlyPriceUsd),
+      billingCurrency: input.billingCurrency,
+    },
+    orderBy: {
+      createdAt: "asc",
+    },
+  });
+
+  if (!candidate) {
+    return;
+  }
+
+  await database.subscriptionPlan.update({
+    where: {
+      id: candidate.id,
+    },
+    data: {
+      code: input.code,
+      displayName: input.displayName,
+      isActive: true,
+    },
+  });
+}