Detailed wiki content repair: Setup

Setup.md

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+# Setup
+
+## Proven Setup Signals
+
+| Signal | Detail |
+|---|---|
+| platformio.ini | envs=esp32dev; boards=esp32dev; frameworks=arduino |
+| Arduino sketches | ESP32-PortaPack-Mesh-Network-Project/MASTER-esp.ino, ESP32-PortaPack-Mesh-Network-Project/SLAVE-esp.ino |
+| README files | ESP32-PortaPack-Mesh-Network-Project/README.md, README.md |
+
+## Setup Path
+
+- Use PlatformIO for firmware builds; confirm environment and board before flashing.
+- Open Arduino sketches only after confirming board package, library dependencies, and target board.
+
+## Environment Rules
+
+- Keep local secrets out of Git.
+- Put generated build output outside source control.
+- Prefer a clean checkout when validating setup instructions.
+- Record the exact command that works in the readiness issue before closing it.
+
+## Current Gaps
+
+- No setup gaps were inferred from inspected evidence.