fix: review fixes for the ESP32-P4 build

- The pre-v3 build is for chips before v2.0, not v3.0: the esp32p4_es
  libraries stop at v1.99.  The CI label and comments say so, and that no
  build runs on v2.x or v3.00.
- A save refuses a clock mode the chip can't use: ProtoSettings takes
  CLKMode 0-ETH_CLOCK_ID_MAX, 0 only on the P4.  Before, 1-3 saved and
  then stopped Ethernet at the next start.  A range of one value reads
  "must be 0".
- Tests for the pin limit (54 taken, 55 refused) and the clock limits.
- The web UI's P4 pins leave out strapping pin 36 too.
- The preset says ESP32-P4-WIFI6-POE-ETH, the board's name.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/adr/0003-pioarduino-idf55.md

@@ -15,8 +15,8 @@ We moved every firmware env from `espressif32 @ 6.13.0` (Arduino 2.0.17 on ESP-I
 
   > **Amended by [ADR 0006](0006-two-security-modes-eleven-http-routes.md) (4.0.0).** The C3 builds again. Without the old API (ports 8080 and 8081), its image is 1,498,512 bytes at level 2 and leaves 72.6 KB of the OTA slot. It runs on chip revision v0.3 or later only: the framework's C3 libraries are built with `CONFIG_ESP32C3_REV_MIN_3`. Its default radio pins moved off GPIO 12-17, which hold the SPI flash.
 - **The C5 is updated over USB.** New in 4.0.0. At level 2 its image left 3.4 KB of the OTA slot, under CI's 8 KB, so like the C6 it is released as a debug build with one 3 MB app slot (`esp32_huge_app.csv`), which no OTA can write. The framework's C5 libraries run on chip revision v1.0 or later only (`CONFIG_ESP32C5_REV_MIN_FULL=100`). Its WiFi has 5 GHz too, so the passive scans for the configured network (`src/ESPNetwork.cpp`, 300 ms a channel) cover about 38 channels instead of 13: about 11 s instead of 4 s, depending on the country's channels.
-- **The P4 has two builds.** New in 4.0.0, for boards such as Waveshare's ESP32-P4-WIFI6-POE-ETH. The framework's P4 libraries run on chip revision v3.01 or later only (`CONFIG_ESP32P4_REV_MIN_FULL=301`), its `esp32p4_es` libraries on revisions before v2.0, so `esp32p4` (chip model `p4`) and `esp32p4es` (`p4es`) each get their own release files. Both keep the OTA slot: at level 2 their images leave about 128 KB. WiFi goes through the board's ESP32-C6 on SDIO (esp-hosted, the framework's pins 14-19 and reset 54), so the C6 has to run a matching esp-hosted slave firmware, which Waveshare's boards ship with.
-- **Ethernet PHY ids are ours.** Arduino 3.x renumbered `eth_phy_type_t` (`ETH_PHY_GENERIC` is 0). NVS, backups and the web UI keep the Arduino 2.x numbers as `eth_phy_id_t` (`src/EthPhy.h`), translated by name when Ethernet starts. Never cast a stored id to the framework enum. The RMII clock mode is kept the same way, as `eth_clock_id_t` in the ESP32's numbering: the P4's `eth_clock_mode_t` is the IDF's `emac_rmii_clock_mode_t`, whose 0 is a deprecated default. On the P4 only clock in (GPIO 50) translates, since `ETH.begin()` keeps the clock on that pin.
+- **The P4 has two builds.** New in 4.0.0, for boards such as Waveshare's ESP32-P4-WIFI6-POE-ETH. The framework's P4 libraries run on chip revision v3.01 or later only (`CONFIG_ESP32P4_REV_MIN_FULL=301`), its `esp32p4_es` libraries on revisions before v2.0, so `esp32p4` (chip model `p4`) and `esp32p4es` (`p4es`) each get their own release files. No build runs on v2.x or v3.00. Both keep the OTA slot: at level 2 their images leave about 128 KB. WiFi goes through the board's ESP32-C6 on SDIO (esp-hosted, the framework's pins 14-19 and reset 54), so the C6 has to run a matching esp-hosted slave firmware, which Waveshare's boards ship with.
+- **Ethernet PHY ids are ours.** Arduino 3.x renumbered `eth_phy_type_t` (`ETH_PHY_GENERIC` is 0). NVS, backups and the web UI keep the Arduino 2.x numbers as `eth_phy_id_t` (`src/EthPhy.h`), translated by name when Ethernet starts. Never cast a stored id to the framework enum. The RMII clock mode is kept the same way, as `eth_clock_id_t` in the ESP32's numbering: the P4's `eth_clock_mode_t` is the IDF's `emac_rmii_clock_mode_t`, whose 0 is a deprecated default. On the P4 only clock in (GPIO 50) translates, since `ETH.begin()` keeps the clock on that pin, and a save refuses the others (`ETH_CLOCK_ID_MAX`).
 - **Ethernet only on the original ESP32 and the P4.** Arduino 3.x has the RMII MAC API only where `CONFIG_ETH_USE_ESP32_EMAC` is set. S3, C3, C5 and C6 build without Ethernet.
 - **Updates roll back until proven.** We override the core's `verifyRollbackLater()` hook to return true, and `loop()` marks the new firmware valid once it has run 60 s and the network is up. A reset before then boots the previous firmware. The LittleFS image an update wrote stays, so the old firmware runs with the new web UI.
 - **Tooling.** pioarduino needs its own Core fork (`pip install pioarduino`, the pioarduino IDE extension in VS Code), which it installs into `~/.platformio/penv` in place of PlatformIO Core.