feat: prove build, flashing, and stable basic operation

PLANS.md

@@ -114,7 +114,7 @@ If all criteria pass, set this milestone to `DONE`, append its execution record,
 
 ## Milestone 001 — Prove build, flashing, and stable basic operation
 
-**Status:** `IN PROGRESS`  
+**Status:** `DONE`  
 **Depends on:** Milestone 000
 
 ### Objective
@@ -153,11 +153,21 @@ Prove that the configuration selected in Milestone 000 works reliably on the phy
 
 If all criteria pass, set this milestone to `DONE`, append its execution record, and change Milestone 002 from `BLOCKED` to `READY`.
 
+Execution record
+- Date: 2026-08-27
+- Board model and revision: ESP32-C6FH4 QFN32, revision v0.2; the carrier board remains an unidentified SuperMini-style ESP32-C6 Mini.
+- Toolchain and library versions: PlatformIO Core 6.1.19; `espressif32` 7.0.1; ESP-IDF 6.0.1; esptool.py 4.11.0; RISC-V toolchain 15.2.0+20251204.
+- Result: PASS
+- Evidence: `src/main.c` now logs reset reason, chip details, flash size, uptime, free heap, and minimum free heap every 30 seconds without Wi-Fi. `platformio.ini`, `sdkconfig.esp32-c6-devkitm-1`, and `partitions.csv` pin the platform, configure 4 MB flash, and select a verified 2 MB factory application plus 1,984 KB LittleFS partition. Four successful esptool upload cycles detected the ESP32-C6FH4 with 4 MB embedded flash, verified all written hashes, and hard-reset the board. The final upload wrote the bootloader at `0x0`, partition table at `0x8000`, and firmware at `0x10000`; decoding `.pio/build/esp32-c6-devkitm-1/partitions.bin` confirmed the configured NVS, PHY, factory, and LittleFS partitions. On 2026-08-27, the user reported that the no-Wi-Fi two-hour run completed successfully and confirmed that removing and restoring USB power produced a normal boot.
+- Measurements: Final clean build: RAM 11,116 / 327,680 bytes (3.4%); firmware 161,288 / 2,097,152 bytes (7.7%). Device diagnostics repeatedly reported `reset_reason=usb`, `flash_bytes=4194304`, `free_heap_bytes=470012`, and `min_free_heap_bytes=470012` from uptime 15 to 195 seconds, with no error, watchdog, or unexpected restart observed. The candidate GPIO8 probe completed while native USB serial remained available.
+- Issues or deviations: `pio test -e esp32-c6-devkitm-1 --without-uploading` found no test suites in `test/`. The user explicitly directed that visual confirmation of the GPIO8 LED probe be skipped; the LED wiring and polarity remain unconfirmed and must not be relied on by future work.
+- Next action: Milestone 002 is ready but is not started as part of this milestone.
+
 ---
 
 ## Milestone 002 — Prove the Wi-Fi, LittleFS, and HTTP vertical slice
 
-**Status:** `BLOCKED`  
+**Status:** `READY`  
 **Depends on:** Milestone 001
 
 ### Objective