B1: platformio.ini - pioarduino platform, board and memory flags #183

_{Recreated from Strycher/Field_Compass-archive#183 — originally opened by @Strycher on 2026-08-09. Credentials redacted where present.}

Epic: #154

First step of the migration. Creates platformio.ini only - no source moves, no library pinning.

platform = https://github.com/pioarduino/platform-espressif32/releases/download/53.03.13-1/platform-espressif32.zip
framework = arduino

Not platformio/espressif32 - Espressif stopped maintaining PlatformIO support and the official platform tops out at Arduino core 2.x. Field Compass is on 3.3.8. This is the platform string the meshcore and Crosswire projects already use.

The flag that will silently ruin your day

board_build.arduino.memory_type must match the board's PSRAM wiring. Wrong value and PSRAM does not appear - no build error, just a board that boots with the LVGL draw buffers and the LVGL heap (#164) unable to allocate. Both live in PSRAM now.

Board: Adafruit ESP32-S3 Feather, 4MB flash / 2MB quad PSRAM (PID 5477). Core version and FQBN are recorded in docs/library-manifest.md.

Scope

platformio.ini with platform, board, framework, PSRAM/partition/flash settings and monitor_speed. Nothing else - lib_deps is B3, layout is B4.

Acceptance criteria

• pio run reaches the compile stage (may still fail on missing libs - that is B3)
• Resolved core version is 3.3.8, verified in the build output
• The PSRAM setting carries an inline comment explaining why that value was chosen