refactor(coach): collapse the duplicate daily-cap export to OPERATOR_COST_CAP

The operator-cost cap carried two export names for one value; keep the
accurate one (it gates only the operator-key path) and drop the alias.

src/lib/ai/coach/__tests__/budget.test.ts

@@ -3,7 +3,6 @@ import { describe, expect, it, vi, beforeEach, afterEach } from "vitest";
 import { HttpError } from "@/lib/api-handler";
 import {
   buildDateKey,
-  MAX_TOKENS_PER_USER_PER_DAY,
   OPERATOR_COST_CAP,
   USER_PLAN_CAP,
   resolveDailyCap,
@@ -76,7 +75,7 @@ describe("budget", () => {
 
   it("over-budget throws HttpError(429)", async () => {
     prismaMock.coachUsage.findUnique.mockResolvedValue({
-      totalTokens: MAX_TOKENS_PER_USER_PER_DAY,
+      totalTokens: OPERATOR_COST_CAP,
     });
     const { enforceBudget } = await import("../budget");
     await expect(enforceBudget("user-1", "2026-05-10")).rejects.toMatchObject({
@@ -233,11 +232,13 @@ describe("reconcileSpend cached-token subtraction (F3)", () => {
   });
 });
 
-describe("MAX_TOKENS_PER_USER_PER_DAY (F2 — reasoning-aware operator cap)", () => {
+describe("OPERATOR_COST_CAP (F2 — reasoning-aware operator cap)", () => {
   it("is sized for reasoning turns, not a single non-reasoning reply", () => {
     // Was 25_000 (≈ one gpt-5.x reasoning turn). Raised so the operator-key
     // path survives a normal day of reasoning turns.
-    expect(MAX_TOKENS_PER_USER_PER_DAY).toBeGreaterThanOrEqual(150_000);
-    expect(OPERATOR_COST_CAP).toBe(MAX_TOKENS_PER_USER_PER_DAY);
+    expect(OPERATOR_COST_CAP).toBeGreaterThanOrEqual(150_000);
+    // The user-plan cap is far more generous — a user's own egress is never
+    // gated on the operator-cost ceiling.
+    expect(USER_PLAN_CAP).toBeGreaterThan(OPERATOR_COST_CAP);
   });
 });

src/lib/ai/coach/budget.ts

@@ -34,13 +34,7 @@ import type { ProviderChainType } from "@/lib/ai/provider-chain";
  * surgery) while leaving room for a normal day of reasoning turns on the
  * operator's key. The cap stays a real ceiling on the operator's exposure.
  */
-export const MAX_TOKENS_PER_USER_PER_DAY = 200_000;
-
-/**
- * v1.21.0 (F1) — historical name retained for any external reference; the
- * operator-cost cap is the only cap the ledger enforces.
- */
-export const OPERATOR_COST_CAP = MAX_TOKENS_PER_USER_PER_DAY;
+export const OPERATOR_COST_CAP = 200_000;
 
 /**
  * v1.21.0 (F1) — the daily ceiling for a chain whose egress runs on the
@@ -108,7 +102,7 @@ export async function getDailyTokenSpend(
 export async function enforceBudget(
   userId: string,
   dateKey: string = buildDateKey(),
-  cap: number = MAX_TOKENS_PER_USER_PER_DAY,
+  cap: number = OPERATOR_COST_CAP,
 ): Promise<void> {
   const spent = await getDailyTokenSpend(userId, dateKey);
   if (spent >= cap) {
@@ -148,7 +142,7 @@ export async function reserveBudget(
   userId: string,
   estimatedTokens: number,
   dateKey: string = buildDateKey(),
-  cap: number = MAX_TOKENS_PER_USER_PER_DAY,
+  cap: number = OPERATOR_COST_CAP,
 ): Promise<ReserveBudgetResult> {
   const reserved =
     Number.isFinite(estimatedTokens) && estimatedTokens > 0

src/lib/ai/coach/self-context-questions.ts

@@ -26,7 +26,7 @@ import { singleUserTurn } from "@/lib/ai/types";
 import {
   buildDateKey,
   getDailyTokenSpend,
-  MAX_TOKENS_PER_USER_PER_DAY,
+  OPERATOR_COST_CAP,
   recordSpend,
 } from "@/lib/ai/coach/budget";
 import {
@@ -137,7 +137,7 @@ export async function deriveClarifyingQuestions(
     // Budget gate — same per-day ledger the Coach chat enforces.
     const dateKey = buildDateKey();
     const spent = await getDailyTokenSpend(userId, dateKey);
-    if (spent >= MAX_TOKENS_PER_USER_PER_DAY) return fallback();
+    if (spent >= OPERATOR_COST_CAP) return fallback();
 
     const provider = await resolveProvider(userId);
     // v1.16.6 — same snapshot the Coach chat rides; lets the model