Android: Login and offline mode

Technical specification for authentication and offline operation of the PestControlOS Android app.

Firebase Authentication

Provider: Email/password sign-in via FirebaseAuth.signInWithEmailAndPassword(). User display name is derived from email and passed to Main Activity.
Session: Managed by Firebase Auth SDK; no custom session store. UID and ID token used for Firestore/Storage rules and Cloud Function context.
Identity: User identity is resolved from request.auth.uid in Firestore rules; app may read from a users or staff collection keyed by UID or user ID for display name and role.

Entry point: "Offline login" on the login screen; no Firebase credentials required.
Identity: User enters as "Offline User". No Firestore/Storage access; all data is local or unavailable.
UI restrictions: Main menu shows only Create Report, View Reports, and Logout. Notifications, Work View, Contracts, Jobs, and other Firebase-dependent features are hidden. In View Reports, Stored Reports (Firebase Storage) is hidden.
Offline report creation: Offline users have full access to default offline report creation and offline custom templates. Report selection offers "Custom Report (PDF Template)" and "Create Custom Report"; PDF Template Settings is available; user can choose PestControlOS template or My Template and create as many custom templates as needed, all stored locally and reusable.

All users (authenticated and offline) have the same custom template and custom report capability. There is no distinction: both offline and logged-in users can use PDF Template Settings, create and name custom templates, and reuse them.
Create as many custom templates as needed: Users can save multiple named templates (main header, logo, watermark, header blocks). Each saved template is stored locally (PdfTemplateStorage: SharedPreferences + JSON; logo/watermark files in context.getFilesDir()/pdf_template/). View Templates lists all saved templates; Use opens Create Report with that template; Delete removes it with confirmation. Templates can be reused for any new report.
Default offline report creation: When offline, the app supports full report creation using either the default (PestControlOS) template or any saved custom template. No server required; all generation and storage are local until the user later uploads (when logged in) or shares the file.
Logged-in users: Same access to custom templates and custom report creation as offline users. Logged-in users can create and reuse custom templates, use PestControlOS or My Template, and optionally upload the resulting report to Firebase after save.

Offline mode is a distinct code path: no writes to Firestore/Storage; no reads from Firestore. Local state (e.g. SharedPreferences, PdfTemplateStorage) is used for template settings and saved templates for both offline and authenticated users.
Role and user-ID checks (e.g. 001, 002, 003, 004) apply only when logged in for Firebase-dependent features (Work View, Contracts, Jobs, etc.); custom templates and report creation are available to all users regardless of role.