Document curriculum best practices (e.g., pre-indenting editable regions)

[naomi-freecodecamp]

Description

I'd like to propose adding documentation for curriculum best practices that aren't currently covered. There are important conventions that curriculum contributors should follow, but they're not documented anywhere.

Example: Pre-indenting Editable Regions

One undocumented best practice is that --fcc-editable-region-- areas should be pre-indented appropriately for the camper. This ensures:

• The camper's cursor starts at the correct indentation level
• Code written by campers follows proper formatting from the start
• The learning experience feels polished and professional

Without this documentation, contributors may not realize they should set up the editable region with proper indentation, leading to inconsistent experiences across challenges.

Proposed Solution

Create a "Curriculum Best Practices" guide (or add a section to existing docs) that covers conventions like:

• Pre-indenting editable regions to the appropriate level
• Other formatting standards for seed code
• Common patterns for test assertions
• Guidelines for hint and instruction writing
• Any other tribal knowledge that experienced curriculum contributors know

Benefits

• Reduces back-and-forth in PR reviews
• Ensures consistency across the curriculum
• Helps new curriculum contributors produce quality work faster
• Documents institutional knowledge that currently only exists in reviewers' heads

[majestic-owl448]

all the proposals make sense and would be great additions for contributors