feat(auth): implement JWT authentication and user registration

- Added JWT authentication with token generation and validation.
- Introduced user registration functionality with email and password.
- Integrated Argon2 for password hashing.
- Created SQLite user repository for user data persistence.
- Updated application context to include user repository and configuration settings.
- Added environment variable support for JWT secret and registration allowance.
- Enhanced error handling for unauthorized access and validation errors.
- Updated presentation layer to handle login and registration requests.

crates/application/src/use_cases/login.rs

@@ -0,0 +1,39 @@
+use chrono::{DateTime, Utc};
+use uuid::Uuid;
+
+use domain::{errors::DomainError, value_objects::Email};
+
+use crate::{commands::LoginCommand, context::AppContext};
+
+pub struct LoginResult {
+    pub token: String,
+    pub user_id: Uuid,
+    pub email: String,
+    pub expires_at: DateTime<Utc>,
+}
+
+pub async fn execute(ctx: &AppContext, cmd: LoginCommand) -> Result<LoginResult, DomainError> {
+    let email = Email::new(cmd.email)?;
+    let user = ctx
+        .user_repository
+        .find_by_email(&email)
+        .await?
+        .ok_or_else(|| DomainError::Unauthorized("Invalid credentials".into()))?;
+
+    let valid = ctx
+        .password_hasher
+        .verify(&cmd.password, user.password_hash())
+        .await?;
+    if !valid {
+        return Err(DomainError::Unauthorized("Invalid credentials".into()));
+    }
+
+    let generated = ctx.auth_service.generate_token(user.id()).await?;
+
+    Ok(LoginResult {
+        token: generated.token,
+        user_id: user.id().value(),
+        email: user.email().value().to_string(),
+        expires_at: generated.expires_at,
+    })
+}

crates/application/src/use_cases/mod.rs

@@ -1,4 +1,6 @@
 pub mod get_diary;
 pub mod get_review_history;
 pub mod log_review;
+pub mod login;
+pub mod register;
 pub mod sync_poster;

crates/application/src/use_cases/register.rs

@@ -0,0 +1,18 @@
+use domain::{errors::DomainError, models::User, value_objects::Email};
+
+use crate::{commands::RegisterCommand, context::AppContext};
+
+pub async fn execute(ctx: &AppContext, cmd: RegisterCommand) -> Result<(), DomainError> {
+    if !ctx.config.allow_registration {
+        return Err(DomainError::Unauthorized("Registration is disabled".into()));
+    }
+
+    let email = Email::new(cmd.email)?;
+
+    if ctx.user_repository.find_by_email(&email).await?.is_some() {
+        return Err(DomainError::ValidationError("Email already registered".into()));
+    }
+
+    let hash = ctx.password_hasher.hash(&cmd.password).await?;
+    ctx.user_repository.save(&User::new(email, hash)).await
+}