refactor: Remove library and tools after migration to dedicated repos.

[nedseb]

Context

As part of the restructuring, steami_screen moves to micropython-steami-lib and the simulation/validation tools move to micropython-steami-tools. This repo keeps only the tutorials.

What to remove

Path	Moved to
lib/steami_screen.py	micropython-steami-lib#266
lib/steami_colors.py	micropython-steami-lib#266
lib/steami_ssd1327.py	micropython-steami-lib#266
lib/steami_gc9a01.py	micropython-steami-lib#266
sim/sim_backend.py	micropython-steami-tools#1
validate.py	micropython-steami-tools#1
generate_report.py	micropython-steami-tools#1
tools/board_validate.py	micropython-steami-tools#1
docs/mockups/	micropython-steami-tools#1

Tasks

• Wait for micropython-steami-lib#266 (steami_screen migration)
• Wait for micropython-steami-tools#1 (tools migration)
• Remove lib/ directory entirely
• Remove sim/ directory
• Remove validate.py, generate_report.py, tools/
• Remove docs/mockups/
• Adapt tutorials/*/screenshot.py imports (15 files) to reference steami_screen from micropython-steami-lib
• Adapt tutorials/*/main.py if needed (imports should work with frozen firmware)
• Keep docs/design-constraints.md
• Update README.md

Blocked by

• micropython-steami-lib#266
• micropython-steami-tools#1

Related

• feat: Migrate steami_screen library from tutorials repo. micropython-steami-lib#266 — steami_screen migration
• feat: Scaffold repo and migrate simulation/validation tools. micropython-steami-tools#1 — tools migration