feat: add ExtractYear time function

[authanram]

Problem

When building time-series analytics, yearly aggregations, or conditional counts based on years, developers currently need to fall back to DB::raw() with database-specific SQL:

// MySQL
User::select(DB::raw('YEAR(created_at) as year'))->groupBy(DB::raw('YEAR(created_at)'));

// PostgreSQL
User::select(DB::raw('EXTRACT(YEAR FROM created_at)::int as year'))->groupBy(DB::raw('EXTRACT(YEAR FROM created_at)'));

// SQLite
User::select(DB::raw("CAST(strftime('%Y', created_at) AS INTEGER) as year"))->groupBy(DB::raw("strftime('%Y', created_at)"));

This defeats the purpose of the query-expressions package and forces developers to write database-specific code or maintain multiple query variants.

Solution

Add an ExtractYear expression that generates the appropriate SQL for each supported database:

use Tpetry\QueryExpressions\Function\Time\ExtractYear;

// Works on all supported databases
User::select([
    new Alias(new ExtractYear('created_at'), 'year'),
    new Count('*'),
])->groupBy(new ExtractYear('created_at'))->get();

// Combine with CountFilter for multi-year statistics in a single query
Movie::select([
    new Alias(new CountFilter(new Equal(new ExtractYear('released_at'), new Value(2023))), 'count_2023'),
    new Alias(new CountFilter(new Equal(new ExtractYear('released_at'), new Value(2024))), 'count_2024'),
])->first();

Database	Generated SQL
MySQL/MariaDB	year(column)
PostgreSQL	extract(year from column)::int
SQLite	cast(strftime('%Y', column) as integer)
SQL Server	year(column)