v2.5.0: History chart, web export, and marquee fix for nearest airport

Adds a 7-day bar-chart view of the flight logbook (Menu -> Flight
Options -> History chart), and a small built-in web server that
serves a logbook overview page plus a merged CSV export of all
logged days once the device is connected to WiFi (discoverable via
the "?" button on the Logbook files screen, which now also shows the
live device IP). Also fixes the "nearest airport" line on the
Location Presets screen, which previously used tft.setViewport() and
went completely invisible with our custom font - it now scrolls as a
proper marquee without relying on the viewport clip.

Also documents the standard release workflow in CLAUDE.md.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

README.md

@@ -35,6 +35,8 @@ You can flash the firmware directly from your browser to your CYD display withou
 - **Location presets** – save up to 3 fixed locations, or point the radar at any place in the world (see [Location Presets](#-location-presets) below)
 - **Aircraft watchlist** – track up to 5 specific flights by callsign, with a cyan radar ring and blue LED alert when one appears (see [Watchlist](#-watchlist) below)
 - **Night dimming** – automatically dims the backlight to a softer (but still readable) level between 22:00 and 06:00 local time (see [Night Dimming](#-night-dimming) below)
+- **History chart** – a simple 7-day bar chart of logged aircraft counts, right next to the plain logbook file list (see [History Chart](#-history-chart) below)
+- **Web export** – a small built-in web page (reachable via the device's IP while on the same WiFi) to download the complete flight logbook as one merged CSV file (see [Web Export](#-web-export) below)
 - **IP-based geolocation** (no GPS module needed) to center the radar on your location
 - **Proximity LED alert** – the onboard RGB LED blinks green when an aircraft is within 3 km (no speaker on this board, so this replaces an audible alert)
 - **Dual-core design** – all networking (WiFi, ADS-B polling, aircraft detail lookups) runs on Core 0, while the display and touch input run on Core 1, so the UI never freezes during a network request
@@ -106,9 +108,23 @@ Shows at a glance:
 
 The **"Reset logbook data"** button (tap twice to confirm) permanently deletes all logged data.
 
+### 📈 History Chart
+Shows the last up to **7 days** from the flight logbook as a simple bar chart – a quick visual complement to the plain number list in Logbook files. Bar height is relative to the busiest day shown, with the exact count printed above each bar and the day-of-month printed below it.
+
+**Good for:** spotting at a glance which days were busier than others, without having to compare numbers row by row.
+
+A "?" info button on the History chart screen explains how it works directly on the device.
+
 ### 📁 Logbook files
 Lists the last several days from the logbook individually, with date and the number of aircraft logged that day. Handy for tracing the history over multiple days instead of only seeing the grand total.
 
+### 🌐 Web Export
+In addition to viewing the logbook on the device itself, a small built-in web page lets you export the **complete flight logbook** as a single merged CSV file – handy for opening in Excel, Numbers, or Google Sheets. It starts automatically in the background as soon as the device connects to WiFi. Deliberately **export-only, no live radar tracking over the web** – that would just burn resources for little benefit.
+
+**How to use it:** while your computer or phone is on the same WiFi network as the device, open a browser and go to the device's IP address (e.g. `http://192.168.1.42/`). The page lists every logged day with its aircraft count and a download link for the merged CSV.
+
+Don't know the device's current IP? The "?" info button on the **Logbook files** screen shows it live on the device.
+
 ### 📖 Flight logbook (ON/OFF)
 When enabled, the device logs **every newly sighted aircraft** (timestamp, hex code, callsign, registration, type, distance, altitude) into a daily CSV file on the SD card. An aircraft is only logged once per day, even if it crosses the radar multiple times. Survives a same-day restart without logging already-seen aircraft twice. Turning it off saves SD card write cycles if you don't care about the statistics/history.