docs: correct the install and upgrade commands for 21.0.0-rc.1 (#3765)

The upgrade guide and quickstart gave commands that fail with rc.1 on
`next` and Angular 22 on `latest`. The guide now uses one command naming
Angular 21 and `@next`. The quickstart creates the project on Angular 21,
installs `@next`, and says to install firebase-tools 14 first (#3768).

Both follow with `npm install --save-exact @angular/fire@next` to install
the release candidate rather than a canary release (#3766).

The product pages now point at the quickstart.

Author: armando-navarro

README.md

@@ -5,7 +5,7 @@ AngularFire smooths over the rough edges an Angular developer might encounter wh
 [Firebase JS SDK](https://github.com/firebase/firebase-js-sdk) & aims to provide a more natural developer experience
 by conforming to Angular conventions.
 
-<strong><pre>ng add @angular/fire</pre></strong>
+<strong><pre>ng add @angular/fire@next</pre></strong>
 
 - **Dependency injection** - Provide and Inject Firebase services in your components.
 - **Zone.js wrappers** - Stable zones allow proper functionality of service workers, forms, SSR, and pre-rendering.

docs/ai.md

@@ -8,14 +8,11 @@ Firebase AI Logic gives you access to the latest generative AI models from Googl
 
 [Learn more](https://firebase.google.com/docs/ai-logic)
 
-> Firebase AI Logic was previously called **Vertex AI in Firebase**. If you are upgrading from AngularFire 20, the module moved from `@angular/fire/vertexai` to `@angular/fire/ai` and most symbols were renamed (`provideVertexAI` to `provideAI`, `VertexAI` to `AI`). One is not a rename: plain `getAI()` uses the Gemini Developer API backend, so the old `getVertexAI()` maps to `getAI(app, { backend: new AgentPlatformBackend() })`. Running `ng update @angular/fire` rewrites all of this for you and keeps your app on the same backend, though a call that passed no `location` moves from `us-central1` to `global`. See the [AngularFire 20 to 21 upgrade guide](./version-21-upgrade.md).
+> Firebase AI Logic was previously called **Vertex AI in Firebase**. If you are upgrading from AngularFire 20, the module moved from `@angular/fire/vertexai` to `@angular/fire/ai` and most symbols were renamed (`provideVertexAI` to `provideAI`, `VertexAI` to `AI`). One is not a rename: plain `getAI()` uses the Gemini Developer API backend, so the old `getVertexAI()` maps to `getAI(app, { backend: new AgentPlatformBackend() })`. Running the `ng update` command in the [AngularFire 20 to 21 upgrade guide](./version-21-upgrade.md) rewrites all of this for you and keeps your app on the same backend, though a call that passed no `location` moves from `us-central1` to `global`.
 
 ## Dependency Injection
 
-As a prerequisite, ensure that `AngularFire` has been added to your project via
-```bash
-ng add @angular/fire
-```
+As a prerequisite, ensure that `AngularFire` has been added to your project as described in the [Quickstart](./install-and-setup.md).
 
 Provide an AI instance in the application's `app.config.ts`:
 

docs/analytics.md

@@ -12,10 +12,7 @@ Google Analytics is an app measurement solution, available at no charge, that pr
 
 ## Dependency Injection
 
-As a prerequisite, ensure that `AngularFire` has been added to your project via
-```bash
-ng add @angular/fire
-```
+As a prerequisite, ensure that `AngularFire` has been added to your project as described in the [Quickstart](./install-and-setup.md).
 
 Provide an Analytics instance in the application's `app.config.ts`:
 

docs/app-check.md

@@ -12,10 +12,7 @@ App Check helps protect your API resources from abuse by preventing unauthorized
 
 ## Dependency Injection
 
-As a prerequisite, ensure that `AngularFire` has been added to your project via
-```bash
-ng add @angular/fire
-```
+As a prerequisite, ensure that `AngularFire` has been added to your project as described in the [Quickstart](./install-and-setup.md).
 
 Provide an App Check instance in the application's `app.config.ts`:
 

docs/auth.md

@@ -15,10 +15,7 @@ Firebase Authentication integrates tightly with other Firebase services, and it
 
 ## Dependency Injection
 
-As a prerequisite, ensure that `AngularFire` has been added to your project via
-```bash
-ng add @angular/fire
-```
+As a prerequisite, ensure that `AngularFire` has been added to your project as described in the [Quickstart](./install-and-setup.md).
 
 Provide an Auth instance in the application's `app.config.ts`:
 

docs/data-connect.md

@@ -10,10 +10,7 @@ Firebase Data Connect (now known as "Firebase SQL Connect" in the Firebase docum
 
 ## Dependency Injection
 
-As a prerequisite, ensure that `AngularFire` has been added to your project via
-```bash
-ng add @angular/fire
-```
+As a prerequisite, ensure that `AngularFire` has been added to your project as described in the [Quickstart](./install-and-setup.md).
 
 Provide a Data Connect instance in the application's `app.config.ts`. `getDataConnect` takes a connector config that identifies your service, connector, and location; this is generated for you when you set up Data Connect and is also exported from your generated SDK:
 

docs/database.md

@@ -12,10 +12,7 @@ The Firebase Realtime Database is a cloud-hosted database. Data is stored as JSO
 
 ## Dependency Injection
 
-As a prerequisite, ensure that `AngularFire` has been added to your project via
-```bash
-ng add @angular/fire
-```
+As a prerequisite, ensure that `AngularFire` has been added to your project as described in the [Quickstart](./install-and-setup.md).
 
 Provide a Database instance in the application's `app.config.ts`:
 

docs/firestore.md

@@ -14,10 +14,7 @@ Cloud Firestore is the API that gives your application access to your database i
 
 ## Dependency Injection
 
-As a prerequisite, ensure that `AngularFire` has been added to your project via
-```bash
-ng add @angular/fire
-```
+As a prerequisite, ensure that `AngularFire` has been added to your project as described in the [Quickstart](./install-and-setup.md).
 Provide a Firestore instance in the application's `app.config.ts`:
 
 ```ts

docs/functions.md

@@ -12,10 +12,7 @@ The Cloud Functions for Firebase client SDKs let you call functions directly fro
 
 ## Dependency Injection
 
-As a prerequisite, ensure that `AngularFire` has been added to your project via
-```bash
-ng add @angular/fire
-```
+As a prerequisite, ensure that `AngularFire` has been added to your project as described in the [Quickstart](./install-and-setup.md).
 
 Provide a Cloud Functions instance in the application's `app.config.ts`:
 

docs/install-and-setup.md

@@ -2,46 +2,56 @@
 
 ## Before you begin
 
-- **Firebase CLI.** Setup uses the Firebase CLI (`firebase-tools`), version 14 or newer. `ng add` installs it if it is missing and prompts you to sign in, so you do not have to install it yourself first. It does not upgrade a copy you already have, so an older one stops setup with `firebase-tools version 14.0.0+ is required, please upgrade and run again`. To handle it ahead of time, or to clear that error, run `npm install -g firebase-tools` then `firebase login`.
-- **On the newest Angular major, use `@next`.** If `ng add @angular/fire` reports an Angular peer-dependency conflict, your Angular version is newer than AngularFire's default (`latest`) release. Install the version-matched pre-release instead: `ng add @angular/fire@next`.
+- **Firebase CLI**
+  - Setup uses the Firebase CLI (`firebase-tools`). Install version 14 first, with `npm install -g firebase-tools@14`, then `firebase login`.
+  - With no CLI on the machine, `ng add` installs the newest version for you, and on version 15 setup stops right after the features question with `Cannot read properties of undefined (reading 'email')` (#3768).
+  - A copy older than 14 stops setup with `firebase-tools version 14.0.0+ is required, please upgrade and run again`, and `ng add` does not upgrade a copy you already have.
 - **Harmless CLI noise.** The Firebase CLI may print a `punycode` deprecation warning or ask about enabling extra features (for example Gemini) during setup. These come from the CLI, not from AngularFire, and are safe to ignore.
 
 ### 1. Create a new project
 
 ```bash
 # Using yarn create
-yarn create @angular <project-name>
+yarn create @angular@21 <project-name>
 cd <project-name>
 ```
 or 
 
 ```bash
 # Using npm create
-npm create @angular <project-name>
+npm create @angular@21 <project-name>
 cd <project-name>
 ```
 
 optionally installing the tooling directly:
 ```bash
 # Installing the tooling directly
-npm install -g @angular/cli
+npm install -g @angular/cli@21
 ng new <project-name>
 cd <project-name>
 ```
 
-The Angular CLI's `new` command will set up the latest Angular build in a new project structure.
+These commands set up an Angular 21 project, the version AngularFire 21 supports.
 
 ### 2. Install AngularFire and Firebase
 
+AngularFire 21 is currently a release candidate, published under the `next` tag:
+
 ```bash
-ng add @angular/fire
+ng add @angular/fire@next
 ```
 
 This installs AngularFire and configures your project. `ng add` will:
 
 1. Prompt you to select the features to enable and the Firebase project to use, signing you in to Firebase if needed.
 2. Add `provideFirebaseApp(...)`, along with a provider for each feature you select, to your app configuration (for example `app.config.ts`), with your Firebase configuration inlined. No environment files are created.
 
+`ng add` writes the version it installed into your `package.json`, and today that is a canary release such as `21.0.0-rc.1-canary.95b3de1` rather than the release candidate. To replace it with the release candidate, `21.0.0-rc.1`, run:
+
+```bash
+npm install --save-exact @angular/fire@next
+```
+
 ### 3. Inject `Firestore`
 
 Open `/src/app/app.ts` and make the following changes: