feat: add --help flag to run_week.sh and document env vars in check_integrity.sh

[DiogoRibeiro7]

Proposal

run_week.sh

• Only shows usage when `--week_path` is missing
• Should support `-h` / `--help` flag to display usage

check_integrity.sh

• Usage message doesn't document the supported environment variables (`MYSQL_HOST`, `MYSQL_PORT`, `MYSQL_USER`, `MYSQL_PASSWORD`)
• Users must read the script source to discover configuration options

run_week.ps1

• No comment-based help (`<# .SYNOPSIS ... #>`) — PowerShell convention for `Get-Help`

Scope / files impacted

• `scripts/run_week.sh`
• `scripts/check_integrity.sh`
• `scripts/run_week.ps1`