A fully server-side day counter for Minecraft 26.2 / Fabric. Unlike lazy day counters that just read floor(dayTime / 24000) and can jump around, this one counts robustly and needs no client mod.
Server-side only — install it on the server (or use it in singleplayer); vanilla clients see it with no mods installed. Scoreboard sidebar display — shows the day on the right of the screen and automatically hides when a player opens the F3 debug screen. This is the only vanilla HUD element that behaves this way. (It sits vertically-centered on the right and uses the single sidebar slot, so it will conflict with another plugin/datapack that also uses the sidebar.) Switchable position — /daycounter display sidebar|bossbar|actionbar moves it between the three server-controllable vanilla anchors (right-center / top-center / bottom-center). Only the sidebar hides on F3; the choice is remembered across restarts. Time-of-day phase — boss bar and action bar show the current phase (Morning / Afternoon / Evening / Night), and in boss-bar mode the bar fills as the day advances and recolours per phase. Counts skipped nights — sleeping through the night still advances the counter by one day. Works when added late — installed on an already-old world, it seeds from the world's current day (so a 500-day-old world shows Day 500), then keeps counting. Monotonic — natural day passage, skipped nights, and forward /time jumps increase the count; setting the time backwards never decreases it. Persists across restarts — state is stored in the vanilla scoreboard (scoreboard.dat).
