refactor: improve code quality and add comprehensive documentation

Code Quality Improvements:
- Fix hex literal grouping in ID generator (0xB10C_1D -> 0x00B1_0C1D)
- Rename ListQuery::default() to default_query() to avoid confusion with Default trait
- Use div_ceil() instead of manual ceiling division
- Remove unnecessary borrows in auth token generation and hashing
- Simplify nested if statements in error handling

Documentation:
- Add comprehensive authentication section to README
- Document environment variables for server and CLI
- Add security best practices and considerations
- Document password hashing (Argon2id), token storage (SHA-256), and session management
- Include step-by-step authentication setup guide
- Add production deployment recommendations

All 70 tests pass (8 unit + 46 server + 16 CLI) ✅

Co-authored-by: jnsgruk <668505+jnsgruk@users.noreply.github.com>

README.md

@@ -18,26 +18,57 @@ that enables client-side reactivity with [Datastar](https://data-star.dev/).
 
 B{rew}log ships as one executable. You decide whether it acts as a server or a client.
 
-Start the server:
+### First-time setup
+
+On first start, you **must** set an admin password via the `BREWLOG_ADMIN_PASSWORD` environment variable:
 
 ```bash
-brewlog serve
+BREWLOG_ADMIN_PASSWORD="your-secure-password" brewlog serve
 ```
 
-Interact with a running instance via the CLI:
+This creates the admin user in the database. On subsequent starts, the password is not required.
+
+### Authentication
+
+Brewlog supports two authentication methods:
+
+1. **Web Frontend**: Session-based authentication via login page
+2. **CLI/API**: Token-based authentication via Bearer tokens
+
+#### Web Authentication
+
+1. Start the server and visit `http://localhost:3000`
+2. Click "Login" in the navigation bar
+3. Sign in with username `admin` and your password
+4. You're now authenticated and can create/update/delete records
+
+#### CLI/API Authentication
+
+First, create an API token:
 
 ```bash
-# Point the CLI at your server (defaults to http://127.0.0.1:3000)
+brewlog create-token --name "my-cli-token"
+# Enter username: admin
+# Enter password: ****
+# 
+# Token created successfully!
+# Token ID: abc123
+# Token: eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...
+```
+
+Export the token and use it for all CLI commands:
+
+```bash
+export BREWLOG_TOKEN="eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9..."
 export BREWLOG_URL=http://localhost:3000
 
-# Add a roaster
+# Now all write operations work
 brewlog add-roaster \
   --name "Radical Roasters" \
   --country "UK" \
   --city "Bristol" \
   --homepage "https://radicalroasters.co.uk"
 
-# Add a roast metadata and tasting notes
 brewlog add-roast \
   --roaster-id "deadbeef" \
   --name "Chelbesa Lot 2" \
@@ -48,15 +79,27 @@ brewlog add-roast \
   --tasting-notes "Blueberry, Jasmine"
 ```
 
-Every CLI command maps to an HTTP endpoint. You can perform the same operations with `curl`,
-Postman, or any HTTP client:
+#### Token Management
+
+```bash
+# List your active tokens
+brewlog list-tokens
+
+# Revoke a token
+brewlog revoke-token --id abc123
+```
+
+#### API Usage
+
+For direct API access, include your token as a Bearer token:
 
 ```bash
 curl http://localhost:3000/api/v1/roasters \
-    --json '{"name":"Radical Roasters","country":"UK","city":"Bristol","homepage":"https://radicalroasters.co.uk"}'
+  -H "Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9..." \
+  --json '{"name":"Radical Roasters","country":"UK"}'
 ```
 
-Once the server is running, visit `http://localhost:3000` to access the user interface.
+**Note**: All read operations (GET requests) are public and don't require authentication. Only write operations (POST/PUT/DELETE) require authentication.
 
 ## Installation
 
@@ -75,3 +118,62 @@ During development you can run directly:
 ```bash
 cargo run -- serve
 ```
+
+## Environment Variables
+
+### Server Configuration
+
+- **`BREWLOG_ADMIN_PASSWORD`** *(required on first start)*: Sets the admin user password. Must be provided when starting the server for the first time.
+- **`BREWLOG_SECURE_COOKIES`**: Set to `"true"` to enable the `Secure` flag on session cookies (HTTPS-only transmission). Recommended for production deployments.
+- **`DATABASE_URL`**: SQLite database file path (default: `brewlog.db`)
+- **`BIND_ADDRESS`**: Server bind address (default: `0.0.0.0:3000`)
+
+### CLI Configuration
+
+- **`BREWLOG_URL`**: API server URL (default: `http://127.0.0.1:3000`)
+- **`BREWLOG_TOKEN`**: API authentication token for write operations
+
+## Security Considerations
+
+### Password Security
+
+- Passwords are hashed using **Argon2id** with industry-standard secure defaults
+- Password hashing uses constant-time comparison to prevent timing attacks
+- Never store passwords in plain text - always use the password prompt
+
+### Token Security
+
+- API tokens are cryptographically secure 32-byte random values
+- Tokens are stored as **SHA-256 hashes** in the database
+- Token values are only displayed **once** at creation time
+- Revoked tokens cannot be reused
+
+### Session Security
+
+- Session tokens are 256-bit cryptographically secure random values
+- Sessions are stored in the database with 30-day expiration
+- Session tokens are hashed with **SHA-256** before storage
+- Cookies are **HttpOnly** and **SameSite=Strict** for CSRF protection
+- Sessions are properly invalidated on logout
+
+### Production Deployment
+
+When deploying to production:
+
+1. **Enable HTTPS**: Set `BREWLOG_SECURE_COOKIES=true` to ensure cookies are only transmitted over HTTPS
+2. **Use Strong Passwords**: Choose a strong admin password (12+ characters, mixed case, numbers, symbols)
+3. **Restrict Access**: Use firewall rules to limit who can access the server
+4. **Regular Updates**: Keep your Brewlog installation up to date
+5. **Backup Database**: Regularly backup your `brewlog.db` file
+6. **Revoke Unused Tokens**: Periodically review and revoke API tokens you no longer need
+
+### Authentication Model
+
+Brewlog uses a **single-user** authentication model:
+
+- Only one user account exists (`admin`)
+- No sign-up or password recovery flows
+- No multi-user support or permissions
+- All authenticated users have full access to all operations
+
+This design assumes Brewlog is deployed for **personal use** or in a **trusted environment**.

src/cli/tokens.rs

@@ -33,7 +33,7 @@ pub async fn create_token(client: &BrewlogClient, cmd: CreateTokenCommand) -> Re
     // Create the token
     let token_response = client
         .tokens()
-        .create(&username, &password, &cmd.name)
+        .create(username, &password, &cmd.name)
         .await?;
 
     println!("\nToken created successfully!");

src/domain/ids.rs

@@ -3,7 +3,7 @@ use once_cell::sync::Lazy;
 use rand::RngCore;
 
 static ID_GENERATOR: Lazy<BlockIdGenerator<char>> =
-    Lazy::new(|| BlockIdGenerator::new(Alphabet::alphanumeric(), 0xB10C_1D_u128, 4));
+    Lazy::new(|| BlockIdGenerator::new(Alphabet::alphanumeric(), 0x00B1_0C1D_u128, 4));
 
 pub fn generate_id() -> String {
     let mut rng = rand::thread_rng();

src/domain/listing.rs

@@ -97,7 +97,7 @@ impl<K: SortKey> ListRequest<K> {
         }
     }
 
-    pub fn default() -> Self {
+    pub fn default_query() -> Self {
         let key = K::default();
         Self::new(
             1,
@@ -164,7 +164,7 @@ impl<K: SortKey> ListRequest<K> {
             return Self::new(1, self.page_size, self.sort_key, self.sort_direction);
         }
 
-        let last_page = ((total + limit as u64 - 1) / limit as u64) as u32;
+        let last_page = (total.div_ceil(limit as u64)) as u32;
         let adjusted_page = self.page.min(last_page.max(1));
         Self::new(
             adjusted_page,
@@ -200,7 +200,7 @@ impl<T> Page<T> {
             1
         } else {
             let size = self.page_size as u64;
-            ((self.total + size - 1) / size) as u32
+            (self.total.div_ceil(size)) as u32
         }
     }
 

src/infrastructure/auth.rs

@@ -38,7 +38,7 @@ pub fn verify_password(password: &str, password_hash: &str) -> Result<bool> {
 pub fn generate_token() -> Result<String> {
     let mut token_bytes = [0u8; 32];
     OsRng.fill_bytes(&mut token_bytes);
-    Ok(general_purpose::STANDARD.encode(&token_bytes))
+    Ok(general_purpose::STANDARD.encode(token_bytes))
 }
 
 /// Hashes a token for storage using SHA-256
@@ -46,14 +46,14 @@ pub fn hash_token(token: &str) -> String {
     let mut hasher = Sha256::new();
     hasher.update(token.as_bytes());
     let result = hasher.finalize();
-    general_purpose::STANDARD.encode(&result)
+    general_purpose::STANDARD.encode(result)
 }
 
 /// Generates a session token for cookie-based authentication
 pub fn generate_session_token() -> String {
     let mut token_bytes = [0u8; 32];
     OsRng.fill_bytes(&mut token_bytes);
-    general_purpose::URL_SAFE_NO_PAD.encode(&token_bytes)
+    general_purpose::URL_SAFE_NO_PAD.encode(token_bytes)
 }
 
 #[cfg(test)]

src/infrastructure/repositories/roasts.rs

@@ -442,11 +442,11 @@ impl RoastRepository for SqlRoastRepository {
 }
 
 fn map_insert_error(err: SqlxError, message: &'static str) -> RepositoryError {
-    if let SqlxError::Database(db_err) = &err {
-        if db_err.code().as_deref() == Some("787") {
+    if let SqlxError::Database(db_err) = &err
+        && db_err.code().as_deref() == Some("787")
+    {
         return RepositoryError::conflict(message);
     }
-    }
 
     RepositoryError::unexpected(err.to_string())
 }

src/infrastructure/repositories/tokens.rs

@@ -51,17 +51,17 @@ impl TokenRepository for SqlTokenRepository {
             .bind(&token.user_id)
             .bind(&token.token_hash)
             .bind(&token.name)
-            .bind(&token.created_at)
-            .bind(&token.last_used_at)
-            .bind(&token.revoked_at)
+            .bind(token.created_at)
+            .bind(token.last_used_at)
+            .bind(token.revoked_at)
             .execute(&self.pool)
             .await
             .map_err(|err| {
-                if let sqlx::Error::Database(db_err) = &err {
-                    if db_err.is_unique_violation() {
+                if let sqlx::Error::Database(db_err) = &err
+                    && db_err.is_unique_violation()
+                {
                     return RepositoryError::conflict("token already exists");
                 }
-                }
                 RepositoryError::unexpected(err.to_string())
             })?;