chore: migrate from Firebase v9 compat to v12 modular API

Replace deprecated firebase/compat/* imports with modular API equivalents
from firebase/app, firebase/database, and firebase/auth. This enables
proper tree-shaking and keeps the library on supported Firebase APIs.

- Bump firebase to ^12.0.0 in package.json and demo/package.json
- Update tsconfig target to ES2020 for Firebase v12 compatibility
- Delete firebase-init.ts compat singleton wrapper
- Rewrite database.ts, document.ts, collection.ts to modular imports
- Fix collection.ts bug: limitToFirst variable reference → props.limitToFirst
- Change signOut from static to instance method (requires Auth instance)
- Add firebase/auth to rollup and build.js externals
- Update CI workflows to Node.js 20 and actions v4

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: jay-cox

.github/workflows/production.yml

@@ -10,12 +10,12 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v2
-      - name: Use Node.js 14.18.3
-        uses: actions/setup-node@v1
+      - uses: actions/checkout@v4
+      - name: Use Node.js 20
+        uses: actions/setup-node@v4
         with:
           registry-url: https://npm.pkg.github.com/
-          node-version: 14.18.3
+          node-version: 20
           cache: 'npm'
       - name: Installing dependencies
         run: npm install

.github/workflows/pull_request.yml

@@ -7,12 +7,12 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v2
-      - name: Use Node.js 14.18.3
-        uses: actions/setup-node@v2
+      - uses: actions/checkout@v4
+      - name: Use Node.js 20
+        uses: actions/setup-node@v4
         with:
           registry-url: https://npm.pkg.github.com/
-          node-version: 14.18.3
+          node-version: 20
           cache: 'npm'
       - name: Intstalling dependencies
         run: npm install
@@ -23,12 +23,12 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v2
-      - name: Use Node.js 14.18.3
-        uses: actions/setup-node@v2
+      - uses: actions/checkout@v4
+      - name: Use Node.js 20
+        uses: actions/setup-node@v4
         with:
           registry-url: https://npm.pkg.github.com/
-          node-version: 14.18.3
+          node-version: 20
           cache: 'npm'
       - name: Installing dependencies
         run: npm install

.github/workflows/version.yml

@@ -17,11 +17,11 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v2
-      - name: Use Node.js 14.18.3
-        uses: actions/setup-node@v1
+      - uses: actions/checkout@v4
+      - name: Use Node.js 20
+        uses: actions/setup-node@v4
         with:
-          node-version: 14.18.3
+          node-version: 20
       - name: Auth github
         run: |
           git config user.email "ci@evite.com"

demo/package.json

@@ -3,7 +3,7 @@
   "version": "0.1.0",
   "private": true,
   "dependencies": {
-    "firebase": "^5.3.0",
+    "firebase": "^12.0.0",
     "react": "^16.4.1",
     "react-dom": "^16.4.1",
     "react-scripts": "1.1.4",

dist/build/types/database.d.ts

@@ -1,6 +1,6 @@
 import React from 'react';
 import { RTDatabase } from './database';
-declare type Args = {
+type Args = {
     database?: RTDatabase;
     path?: string;
     orderByKey?: boolean;
@@ -9,7 +9,7 @@ declare type Args = {
     limitToLast?: number;
     limitToFirst?: number;
 };
-declare type PropTypes = Args;
+type PropTypes = Args;
 /**
  * This function/decorator creates a HOC that wraps the given
  * component and listens to collection events.

dist/build/types/firebase-init.d.ts

@@ -0,0 +1,21 @@
+import type { FirebaseOptions } from 'firebase/app';
+import { Database } from 'firebase/database';
+import { Auth } from 'firebase/auth';
+import type { Persistence, UserCredential } from 'firebase/auth';
+import { Document } from './document';
+type Args = FirebaseOptions & {
+    persistence?: Persistence;
+};
+export declare class RTDatabase {
+    TIMESTAMP: object;
+    fdb: Database;
+    auth: Auth;
+    authPersistence: Persistence;
+    constructor({ persistence, ...config }: Args);
+    get: (path: string) => Document;
+    signInWithCustomToken: (token: string) => Promise<UserCredential>;
+    goOffline: () => void;
+    goOnline: () => void;
+    signOut: () => Promise<void>;
+}
+export {};