Add ScheduleGate

[gjunqueira-sys]

What

Add ScheduleGate to the Top Project Management Tools table.

• CLI that runs the DCMA 14-point schedule assessment on MS Project Excel/CSV exports, fully offline.
• AGPL-3.0 open source with a free Community tier.
• Entry placed alphabetically (R → S → T block) with an objective, greppable description.

Checks

• Link working and points to the project
• Appropriate section (Project Management Tools)
• List kept sorted around the addition
• No trailing whitespace
• One suggestion per PR
• Description short, objective, no marketing language