fix(journal): fail loud in production when secrets are unset

Adds `requireSecret(name, devFallback)` in lib/config.server.ts and
`getDatabaseUrl()` in @trails-cool/db. Both:
- return the env var when set,
- fall back to the dev default in non-production,
- throw at boot in production if the env var is missing OR matches the
  known dev fallback (which would otherwise silently ship a public
  secret / point at localhost).

Applied to:
- JWT_SECRET (lib/jwt.server.ts) — was `?? "dev-jwt-secret-change-in-production"`
- SESSION_SECRET (lib/auth/session.server.ts) — was `?? "dev-secret-change-in-production"`
- DATABASE_URL (server.ts health + boss; packages/db migrate-data) — was
  `?? "postgres://trails:trails@localhost:5432/trails"`

Why: these strings are in the repo and known to attackers. A
misconfigured prod deploy that forgot to set them would either run with
guessable signing keys (full session/JWT forgery) or connect to a
non-existent localhost DB. Better to refuse to start than to silently
operate insecurely.

Tests:
- packages/db/src/get-database-url.test.ts (5 cases)
- lib/config.server.test.ts gains `requireSecret` cases (4 new)

Full repo: pnpm typecheck, pnpm lint, pnpm test all green.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/journal/app/lib/auth/session.server.ts

@@ -9,8 +9,9 @@ import { createCookieSessionStorage, redirect } from "react-router";
 import { eq } from "drizzle-orm";
 import { users } from "@trails-cool/db/schema/journal";
 import { getDb } from "../db.ts";
+import { requireSecret } from "../config.server.ts";
 
-const sessionSecret = process.env.SESSION_SECRET ?? "dev-secret-change-in-production";
+const sessionSecret = requireSecret("SESSION_SECRET", "dev-secret-change-in-production");
 
 export const sessionStorage = createCookieSessionStorage({
   cookie: {

apps/journal/app/lib/config.server.test.ts

@@ -17,3 +17,38 @@ describe("getOrigin", () => {
     expect(getOrigin()).toBe("http://localhost:3000");
   });
 });
+
+describe("requireSecret", () => {
+  beforeEach(() => {
+    vi.resetModules();
+    vi.unstubAllEnvs();
+  });
+
+  it("returns the env value when set in any environment", async () => {
+    vi.stubEnv("NODE_ENV", "production");
+    vi.stubEnv("MY_SECRET", "real-secret");
+    const { requireSecret } = await import("./config.server.ts");
+    expect(requireSecret("MY_SECRET", "dev-fallback")).toBe("real-secret");
+  });
+
+  it("returns the dev fallback when unset in development", async () => {
+    vi.stubEnv("NODE_ENV", "development");
+    delete process.env.MY_SECRET;
+    const { requireSecret } = await import("./config.server.ts");
+    expect(requireSecret("MY_SECRET", "dev-fallback")).toBe("dev-fallback");
+  });
+
+  it("throws in production when the secret is unset", async () => {
+    vi.stubEnv("NODE_ENV", "production");
+    delete process.env.MY_SECRET;
+    const { requireSecret } = await import("./config.server.ts");
+    expect(() => requireSecret("MY_SECRET", "dev-fallback")).toThrow(/MY_SECRET/);
+  });
+
+  it("throws in production when the secret matches the dev fallback", async () => {
+    vi.stubEnv("NODE_ENV", "production");
+    vi.stubEnv("MY_SECRET", "dev-fallback");
+    const { requireSecret } = await import("./config.server.ts");
+    expect(() => requireSecret("MY_SECRET", "dev-fallback")).toThrow(/dev fallback/);
+  });
+});

apps/journal/app/lib/config.server.ts

@@ -5,3 +5,28 @@
 export function getOrigin(): string {
   return process.env.ORIGIN ?? "http://localhost:3000";
 }
+
+/**
+ * Read a required secret from the environment. Returns the env value when
+ * set. In production, throws if the env var is missing or matches the
+ * known-public dev fallback — silently shipping a default secret to prod
+ * is a credential leak. In dev/test, returns the supplied fallback so the
+ * local loop keeps working without ceremony.
+ *
+ * Use this for any value where a leaked default would be a security
+ * incident: signing keys, session secrets, database credentials.
+ */
+export function requireSecret(name: string, devFallback: string): string {
+  const value = process.env[name];
+  const isProd = process.env.NODE_ENV === "production";
+  if (isProd) {
+    if (!value || value === devFallback) {
+      throw new Error(
+        `Refusing to start: ${name} is unset or matches the known-public dev fallback. ` +
+          `Set ${name} to a strong, unique value in production.`,
+      );
+    }
+    return value;
+  }
+  return value ?? devFallback;
+}

apps/journal/app/lib/jwt.server.ts

@@ -1,8 +1,8 @@
 import { SignJWT, jwtVerify } from "jose";
-import { getOrigin } from "./config.server.ts";
+import { getOrigin, requireSecret } from "./config.server.ts";
 
 const JWT_SECRET = new TextEncoder().encode(
-  process.env.JWT_SECRET ?? "dev-jwt-secret-change-in-production",
+  requireSecret("JWT_SECRET", "dev-jwt-secret-change-in-production"),
 );
 
 const ISSUER = getOrigin();