fix: ensure the web UI doesn't break when license telemetry required check fails (#16667)

Addresses https://github.com/coder/coder/issues/16455.

## Changes

- Initialize default entitlements in a Set to include all features
- Initialize entitlements' `Warnings` and `Errors` fields to arrays
rather than `nil`s.
- Minor changes in formatting on the frontend

## Reasoning

I had to change how entitlements are initialized to match the `codersdk`
[generated
types](https://github.com/coder/coder/blob/33d62619225702257fa2542f40ecc26bfd0d1fa6/site/src/api/typesGenerated.ts#L727),
which the frontend assumes are correct, and doesn't run additional
checks on.

- `features: Record<FeatureName, Feature>`: this type signifies that
every `FeatureName` is present in the record, but on `main`, that's not
true if there's a telemetry required error
- `warnings: readonly string[];` and `errors: readonly string[];`: these
types mean that the fields are not `null`, but that's not always true

With a valid license, the [`LicensesEntitlements`
function](https://github.com/coder/coder/blob/33d62619225702257fa2542f40ecc26bfd0d1fa6/enterprise/coderd/license/license.go#L92)
ensures that all features are present in the entitlements. It's called
by the [`Entitlements`
function](https://github.com/coder/coder/blob/33d62619225702257fa2542f40ecc26bfd0d1fa6/enterprise/coderd/license/license.go#L42),
which is called by
[`api.updateEnittlements`](https://github.com/coder/coder/blob/33d62619225702257fa2542f40ecc26bfd0d1fa6/enterprise/coderd/coderd.go#L687).
However, when a license requires telemetry and telemetry is disabled,
the entitlements with all features [are
discarded](https://github.com/coder/coder/blob/33d62619225702257fa2542f40ecc26bfd0d1fa6/enterprise/coderd/coderd.go#L704)
in an early exit from the same function. By initializing entitlements
with all the features from the get go, we avoid this problem.

## License issue banner after the changes

<img width="1512" alt="Screenshot 2025-02-23 at 20 25 42"
src="https://github.com/user-attachments/assets/ee0134b3-f745-45d9-8333-bfa1661e33d2"
/>

coderd/entitlements/entitlements.go

@@ -30,8 +30,8 @@ func New() *Set {
 		// These will be updated when coderd is initialized.
 		entitlements: codersdk.Entitlements{
 			Features:         map[codersdk.FeatureName]codersdk.Feature{},
-			Warnings:         nil,
-			Errors:           nil,
+			Warnings:         []string{},
+			Errors:           []string{},
 			HasLicense:       false,
 			Trial:            false,
 			RequireTelemetry: false,
@@ -39,13 +39,21 @@ func New() *Set {
 		},
 		right2Update: make(chan struct{}, 1),
 	}
+	// Ensure all features are present in the entitlements. Our frontend
+	// expects this.
+	for _, featureName := range codersdk.FeatureNames {
+		s.entitlements.AddFeature(featureName, codersdk.Feature{
+			Entitlement: codersdk.EntitlementNotEntitled,
+			Enabled:     false,
+		})
+	}
 	s.right2Update <- struct{}{} // one token, serialized updates
 	return s
 }
 
 // ErrLicenseRequiresTelemetry is an error returned by a fetch passed to Update to indicate that the
 // fetched license cannot be used because it requires telemetry.
-var ErrLicenseRequiresTelemetry = xerrors.New("License requires telemetry but telemetry is disabled")
+var ErrLicenseRequiresTelemetry = xerrors.New(codersdk.LicenseTelemetryRequiredErrorText)
 
 func (l *Set) Update(ctx context.Context, fetch func(context.Context) (codersdk.Entitlements, error)) error {
 	select {

codersdk/licenses.go

@@ -12,7 +12,8 @@ import (
 )
 
 const (
-	LicenseExpiryClaim = "license_expires"
+	LicenseExpiryClaim                = "license_expires"
+	LicenseTelemetryRequiredErrorText = "License requires telemetry but telemetry is disabled"
 )
 
 type AddLicenseRequest struct {

site/src/api/typesGenerated.ts

@@ -1116,6 +1116,10 @@ export interface License {
 // From codersdk/licenses.go
 export const LicenseExpiryClaim = "license_expires";
 
+// From codersdk/licenses.go
+export const LicenseTelemetryRequiredErrorText =
+	"License requires telemetry but telemetry is disabled";
+
 // From codersdk/deployment.go
 export interface LinkConfig {
 	readonly name: string;

site/src/modules/dashboard/LicenseBanner/LicenseBannerView.tsx

@@ -6,6 +6,7 @@ import {
 	useTheme,
 } from "@emotion/react";
 import Link from "@mui/material/Link";
+import { LicenseTelemetryRequiredErrorText } from "api/typesGenerated";
 import { Expander } from "components/Expander/Expander";
 import { Pill } from "components/Pill/Pill";
 import { type FC, useState } from "react";
@@ -14,6 +15,7 @@ export const Language = {
 	licenseIssue: "License Issue",
 	licenseIssues: (num: number): string => `${num} License Issues`,
 	upgrade: "Contact sales@coder.com.",
+	exception: "Contact sales@coder.com if you need an exception.",
 	exceeded: "It looks like you've exceeded some limits of your license.",
 	lessDetails: "Less",
 	moreDetails: "More",
@@ -26,6 +28,14 @@ const styles = {
 	},
 } satisfies Record<string, Interpolation<Theme>>;
 
+const formatMessage = (message: string) => {
+	// If the message ends with an alphanumeric character, add a period.
+	if (/[a-z0-9]$/i.test(message)) {
+		return `${message}.`;
+	}
+	return message;
+};
+
 export interface LicenseBannerViewProps {
 	errors: readonly string[];
 	warnings: readonly string[];
@@ -57,14 +67,16 @@ export const LicenseBannerView: FC<LicenseBannerViewProps> = ({
 			<div css={containerStyles}>
 				<Pill type={type}>{Language.licenseIssue}</Pill>
 				<div css={styles.leftContent}>
-					<span>{messages[0]}</span>
+					<span>{formatMessage(messages[0])}</span>
 					&nbsp;
 					<Link
 						color={textColor}
 						fontWeight="medium"
 						href="mailto:sales@coder.com"
 					>
-						{Language.upgrade}
+						{messages[0] === LicenseTelemetryRequiredErrorText
+							? Language.exception
+							: Language.upgrade}
 					</Link>
 				</div>
 			</div>
@@ -90,7 +102,7 @@ export const LicenseBannerView: FC<LicenseBannerViewProps> = ({
 					<ul css={{ padding: 8, margin: 0 }}>
 						{messages.map((message) => (
 							<li css={{ margin: 4 }} key={message}>
-								{message}
+								{formatMessage(message)}
 							</li>
 						))}
 					</ul>