docs: reorganize Pico W project documentation and wiring details

[IoTeacher]

Motivation

• Provide a clean, consistent repository structure and clear documentation for a Raspberry Pi Pico W keypad-to-LED project while preserving the original runtime behavior in src/main.cpp.
• Consolidate wiring, component inventory, GPIO mapping, and run/deploy instructions so the project is easy to simulate in Wokwi and flash to real hardware.
• Clarify portability and safety notes (Pico W Wi‑Fi not used, do not commit credentials) and give guidance for Arduino vs Pico SDK workflows.

Description

• Rewrote README.md with a project overview, features, components list, quick GPIO summary, Wokwi simulation steps, and real-hardware flashing guidance while explicitly stating that src/main.cpp behavior is unchanged.
• Expanded docs/wiring.md to include a precise GPIO-to-signal table (rows/columns and all 12 LEDs), passive component notes (r1..r12, rp1..rp4), power/ground checklist, and functional verification steps derived from diagram.json and src/main.cpp.
• Expanded docs/architecture.md to document module responsibilities, runtime flow (setup/loop), the keypad keymap, behavioral contract (group and individual LED actions), and portability guidance for Arduino core vs Pico SDK.
• Added/kept a minimal CMakeLists.txt target documenting build options and retained the original src/main.cpp unchanged in content and behavior.

Testing

• Ran repository inspections and content checks with git status --short and file listing commands to verify changed files were staged and committed, and these commands completed successfully.
• Committed the documentation changes with git add README.md docs/wiring.md docs/architecture.md && git commit -m 'docs: reorganize Pico W project documentation and wiring details' which succeeded and produced a commit (documentation-only change).
• Printed and reviewed the updated files using nl -ba README.md | sed -n '1,220p', nl -ba docs/wiring.md | sed -n '1,220p', nl -ba docs/architecture.md | sed -n '1,220p', and nl -ba src/main.cpp | sed -n '1,220p' to confirm consistency with src/main.cpp pin arrays and behavior; all checks succeeded.

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Codex Task