Simplify database schema: remove card_type, card_id, add card_number

Refactor the database schema to better model the data relationships:

Schema changes:
- Removed cards.card_type (redundant, identical to card_number)
- Removed transactions.card_id (unnecessary indirection)
- Added transactions.card_number (stores card number for all transactions)
- Made cards.customer_id NOT NULL (every card must belong to a customer)
- Made transactions.customer_id nullable (NULL for anonymized transactions)

Import logic changes:
- Only create cards for known customers (transactions with customer_number)
- Store card_number for ALL transactions (including anonymized)
- Skip cards/customer creation for anonymized transactions

Additional changes:
- Add 'db reset' command to drop and recreate database
- Update migration file with new schema

This simplifies queries and better reflects the data model:
- Cards table: authoritative mapping of card_number -> customer_id
- Transactions table: stores all raw data including anonymized cards
- Customer relationship via JOIN on card_number for known customers

src/main.rs

@@ -391,22 +391,27 @@ async fn main() -> anyhow::Result<()> {
                 eprintln!("Usage: {} db <subcommand> [--env <name>]", clean_args[0]);
                 eprintln!("Subcommands:");
                 eprintln!("  setup    Create database and schema");
+                eprintln!("  reset    Drop and recreate database");
                 std::process::exit(1);
             }
 
             println!("Environment: {}", env.as_str());
             let config = Config::load(env)?;
-            let pool = create_pool(&config.database.connection_url()).await?;
-            let repo = Repository::new(pool);
 
             match clean_args[2].as_str() {
                 "setup" => {
+                    let pool = create_pool(&config.database.connection_url()).await?;
+                    let repo = Repository::new(pool);
                     commands::run_db_setup(&repo, &config).await?;
                 }
+                "reset" => {
+                    commands::run_db_reset(&config).await?;
+                }
                 _ => {
                     eprintln!("Unknown db subcommand: {}", clean_args[2]);
                     eprintln!("Subcommands:");
                     eprintln!("  setup    Create database and schema");
+                    eprintln!("  reset    Drop and recreate database");
                     std::process::exit(1);
                 }
             }
@@ -431,6 +436,7 @@ fn print_usage(program: &str) {
     eprintln!("  import <csv-file> [--env <name>]    Import CSV data to database (default: prod)");
     eprintln!("  generate <csv> <dir>               Generate HTML invoices from CSV");
     eprintln!("  db setup [--env <name>]            Create database and schema (default: prod)");
+    eprintln!("  db reset [--env <name>]            Drop and recreate database (default: prod)");
     eprintln!("  help                               Show this help message");
     eprintln!();
     eprintln!("Environments: prod (default), dev, test");