Add NightScout support, Wi-Fi AP setup, QWERTY keyboard, mmol/L, configurable thresholds, and a couple of fixes

[lslomczynski]

Summary

This PR adds several new features and fixes a couple of bugs accumulated since the last sync with upstream. All changes have been tested on a physical ESP32-S3 device with a 320×480 AXS15231B display.

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🆕 New Features

NightScout as a third glucose data source

• New src/NightScout.h / NightScout.cpp: REST API client using GET /api/v1/entries.json with JWT access token passed as ?token= URL parameter
• Connection test via GET /api/v1/status.json (Test button on Account screen)
• Same adaptive polling logic as Dexcom (315 s normal, 90 s stale data, 30 s missed update)
• NightScout direction strings (DoubleUp, SingleUp, FortyFiveUp, Flat, FortyFiveDown, SingleDown, DoubleDown) mapped to existing TrendArrow convention
• clearNightScoutCache() integrated with existing clearData() flow

Account screen updated with a 3-button sensor selector (FreeStyle Libre / Dexcom / NightScout). NightScout section shows URL and Token fields with Edit buttons. All button positions and touch regions computed dynamically from screen width.

Keyboard pages 26/27 added for NightScout URL and Token entry. URL field pre-populated with https:// when empty.

AP setup page, Server.cpp, Stock.cpp all updated for NightScout (radio button, /saveConfig parsing, LittleFS persistence).

All 6 language files updated with 4 new keys: NightScoutIndefini, SetNightScout, NightScoutURL, NightScoutToken.

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Wi-Fi AP first-boot captive portal

When no SSID is configured, the device now shows a choice screen (on-screen setup vs. AP mode) instead of going directly to the Wi-Fi list.

AP mode flow:

• ESP32 starts a soft-AP GlucoMonit-xxxxx with a DNS server for captive portal redirect
• A mobile-friendly dark-theme HTML page (/config) covers: language, timezone, Wi-Fi credentials, sensor type + credentials, glucose thresholds with mg/dL ↔ mmol/L toggle and live colour bar preview
• pageAPInfo screen shows the AP network name, password, and IP address
• Non-blocking restart via esp_timer (one-shot) used throughout to avoid NS_ERROR_NET_EMPTY_RESPONSE caused by blocking the TCP/IP stack before the HTTP response was sent

/eraseConfig split into GET (confirmation page) + POST (actual erase + restart polling page).

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QWERTY / AZERTY keyboard layout

• QWERTY layout added as default for all languages except French
• French language automatically selects AZERTY
• Layout selection is transparent to the rest of the keyboard logic via getAlphaKey() inline helper

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Alternate home screen view

• Tapping the glucose value on the home screen toggles between two views:
  • Normal: standard gauge (donut) + 8-hour bar chart below
  • Alternate: full-screen large gauge (1.5× radius), no bar chart, larger glucose value text
• altView flag persists until next tap or page change

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mmol/L glucose unit support

• User-selectable unit (mg/dL or mmol/L) stored in glucoseUnit
• All display functions (formatGlucoseValue(), getGlucoseUnitLabel()) handle conversion
• pageGlucoseSettings displays and validates values in the selected unit

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Configurable glucose thresholds

New pageGlucoseSettings screen with live colour bar preview for:

• glucoseRangeMin / glucoseRangeMax — gauge scale endpoints (defaults: 0 / 400 mg/dL)
• targetLow / targetHigh — green target range (defaults: 70 / 180 mg/dL)
• glucoseWarn — upper warning threshold (default: 300 mg/dL)

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Polish language

Added pl.h (Polish without diacritical characters) and pl_ogonki.h (an attempt at full Polish with diacritical marks via the UTF-8 → Latin-15 mapping in Gestion.cpp).

Note: pl_ogonki.h is currently not active — getting Polish diacriticals to render correctly on the AXS15231B / u8g2 font stack proved elusive, so pl.h (ASCII-safe Polish) is used for now. pl_ogonki.h is kept in the repository as a starting point for anyone who wants to pick up where this left off.

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Night brightness control

LuminositeNuit (default 10%) applied via PWM when the device clock indicates night hours.

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🐛 Small Fixes

Dexcom

• Fixed DoubleUp / DoubleDown trend arrow mapping (were swapped / missing)
• Reduced fetch window from 24 h (minutes=1440&maxCount=288) to 8 h (minutes=480&maxCount=96) — faster response, matches chart window

NightScout

• Switched getNightScoutReadings() from https.getStream() to https.getString() for reliable buffered HTTPS reads; getStream() is unreliable with chunked transfer encoding on ESP32

FreeStyle Libre

• Stop overwriting user-configured targetLow / targetHigh from the LibreLinkUp API response (the API returns a tight target of 140 mg/dL which silently replaced user settings on every poll)

Wi-Fi

• Fixed premature RecordFichierParametres() on network tap — SSID was saved to flash before the password was confirmed. Added previousSsid backup; Cancel in the password keyboard now restores the original SSID via wifiRestorePreviousSsid()
• Escape double quotes in SSID names in /scanWifi JSON response
• Guard against empty SSID in /saveConfig

Web UI

• Fixed TypeError in JS_Main.js.h: glucoseRangeMax, glucoseRangeMin, glucoseWarn were declared as const in JS_Commun but reassigned in the LoadGlycemie callback — this silently affected gauge, needle, trend arrow and age display in the web dashboard
• Fixed gauge and chart scaling: rangeSpan = glucoseRangeMax - glucoseRangeMin (was using hardcoded glucoseRangeMax as the full span), matching pageAccueil.cpp logic
• Fixed chart background colour bands: replaced stacked overlapping fillRect calls with non-overlapping bands using the seuilCoul[] approach already used on the device screen

Bar chart — 8-hour standardised window

• Chart now always displays the last 8 hours regardless of how many points are stored
• Points older than Tmax − 8 h are skipped via iStart index
• Falls back to the full available range when less than 8 h of data is stored (e.g. shortly after first boot)
• Dexcom and NightScout fetch windows aligned to 8 h

Account screen

• Sensor type buttons (FreeStyle / Dexcom / NightScout) now vertically centre their labels using getTextBounds()-based formula, matching the Bouton_Trace helper

pageCompte — connection test countdown

• After a successful Test, shows a 3-second countdown before navigating to the home screen

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📁 Files Changed

Area	Files
New sensor backend	src/NightScout.h, src/NightScout.cpp
Global state	src/Config.h, src/Config.cpp
Persistence	src/Stock.cpp
Display — home screen	src/Ecran/pageAccueil.cpp, src/Ecran/pageAccueil.h
Display — account	src/Ecran/pageCompte.cpp
Display — keyboard	src/Ecran/pageClavier.cpp
Display — routing	src/Ecran/Gestion.h, src/Ecran/Gestion.cpp
Display — new pages	src/Ecran/pageSetupChoice.*, src/Ecran/pageAPInfo.*, src/Ecran/pageGlucoseSettings.*
Display — settings	src/Ecran/pageAffichage.cpp, src/Ecran/pageConfiguration.cpp, src/Ecran/pageLangue.cpp, src/Ecran/pageWifiList.*
Web server	src/Server.cpp
Networking	src/Internet.cpp, src/Internet.h
Time / brightness	src/Heure.cpp, src/Heure.h
Web assets	src/HTML/JS_Main.js.h, src/HTML/pageMain.h, src/HTML/pageSetupAP.h
Languages	src/Langues/en.h, fr.h, de.h, es.h, it.h, pl.h, pl_ogonki.h, Langue.cpp, Langue.h
Sensor clients	src/Libreview.cpp, src/Dexcom.cpp
Entry point	src/main.cpp
Documentation	README.md, CLAUDE.md, .gitignore

[lslomczynski]

Hello! I forgot to mention in the original post: I allowed myself to propose a different colour logic - similar to those used by Libre and Dexcom where low blood sugar (very dangerous) is 'red' and higher than target is 'yellow'. As for the very high values I was inspired by Glowcose device which uses purple for the higher end of the scale segment. :-)