Add a changelog

CHANGELOG.md

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+# Changelog
+
+Notable changes to the EduCraft server, newest first.
+
+Format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/). Dates
+are the merge date to `main`. A PR number in brackets links the full reasoning,
+which is usually worth reading: several entries below record a wrong diagnosis
+being corrected, and those are the ones most likely to save someone time later.
+
+**Player impact is called out explicitly.** Anything marked
+**REQUIRES PACK RE-IMPORT** means every family must download
+`data/EduCraftClient.mrpack` again or they will be refused at the FML handshake.
+
+## [Unreleased]
+
+### Added
+- Droplet-side security alerting to Discord. A systemd timer runs every 15
+  minutes and reports SSH logins, failed-auth bursts, sensitive sudo, fail2ban
+  bans, container faults, `ops.json` changes, sensitive file edits, new user
+  accounts and a filling disk. Silent otherwise. Installed and running on the
+  droplet; see `alerts/`. [#25, #26]
+
+### Fixed
+- Health check and security alerts rebuilt around zero false positives. Three
+  collectors fired during normal operation, one of which (`RestartCount > 0`)
+  would have alerted on **every run forever** after any deploy, because that
+  counter is cumulative. Restarts are now detected by comparing `StartedAt`.
+  [#26]
+- Manual workflow dispatch no longer posts a status card by default. [#26]
+
+## 2026-08-15
+
+### Added
+- **Server health check** reporting to Discord, running every 30 minutes.
+  Reports three states rather than up/down, because the server answers roughly
+  one ping in four from some networks while being completely healthy, and a
+  one-shot check would page constantly. Deliberately holds no SSH credential:
+  port 22 is open only to DigitalOcean console ranges, so a runner cannot reach
+  the box, and opening it or parking a key in CI would trade a real security
+  boundary for a richer report. [#23, #24]
+
+### Changed
+- **POC mode.** Moderation controls removed: Profanity Guard (chat filter) and
+  `FORCE_GAMEMODE`. Every restriction removed so far had caused an outage or a
+  support incident. The whitelist and `ONLINE_MODE` were deliberately **kept**:
+  they are the difference between a private family server and a public one, and
+  the game port is scanned continuously. Backlog in `specs/0006`. [#22]
+
+### Removed
+- Six Windows-era scripts the droplet made dead: local backup, shutdown and
+  scheduled-task wrappers, plus a UTF-16 command dump from a newer Minecraft
+  than we run. [#21]
+- **The daily playtime limiter went with them, and it had already stopped
+  working.** It capped each child at 120 minutes a day and has not run since the
+  move to the droplet, so that parental control was silently off for weeks.
+  `DEPLOY.md` now says so plainly instead of describing it as merely needing a
+  port. [#21]
+
+## 2026-08-14
+
+### Fixed
+- **Flight enabled**, so Ad Astra works in space. Players stepping out of the
+  ship on the Moon were kicked with "Flying is not enabled on this server":
+  low gravity and jetpacks look identical to the vanilla airborne check. This
+  gives up the last automatic fly-hack check, accepted deliberately given an
+  enforced whitelist, verified accounts, PvP off, and PrismProtect logging every
+  block change. [#20]
+
+### Security
+- The six `mc-image-helper` CVEs assessed and accepted, one critical. They live
+  in the base image and cannot be upgraded from here: a further digest bump
+  would change nothing because upstream still ships helper 1.66.0. The
+  assessment is deliberately **not** uniform, because jackson does parse remote
+  JSON at container start while micrometer and scala are genuinely unreachable.
+  No Trivy ignore file, so the critical stays visible. `specs/0005`. [#18]
+
+## 2026-08-12
+
+### Added
+- **Ad Astra 1.15.20** plus Resourceful Lib, Resourceful Config and Botarium.
+  Rockets, and travel to the Moon, Mars, Venus, Mercury and Glacio with oxygen,
+  space suits and rovers. **REQUIRES PACK RE-IMPORT.** [#17]
+- **When Dungeons Arise 2.1.58.** Large hand-built structures: pirate ships,
+  mountain castles, sky keeps. Server-side only, no player action needed. [#15]
+
+### Changed
+- Memory raised for the new dimensions: heap 4G to 5G, container cap 6g to 6.5g.
+  Deliberately not the 6G discussed, because a JVM needs significant memory
+  outside its heap and setting them equal invites the OOM killer. [#17]
+- Base image bumped to clear two HIGH micrometer CVEs. **It did not work**, and
+  the PR said in advance that the Trivy scan would be the verdict. It was. [#16]
+
+### Fixed
+- **Spawn protection off.** At 16 blocks it silently stopped non-ops placing
+  blocks near world spawn, which had been moved to the owner's house. Minecraft
+  gives no error for this, so it read as the server being broken. [#13]
+- Chunky removed after it appeared to lock players out. **The stated reason was
+  wrong**, and #15 corrected it: reading the jars showed terralith, luckperms,
+  bluemap, prismprotect and playtimestatistics all omit `displayTest`
+  identically, and all were live while people played. The red X is advisory. The
+  real cause of that outage was network loss, not mods. [#14, #15]
+
+## 2026-08-10
+
+### Changed
+- Droplet resized to 4 vCPU and the container cap raised from 2.0 to 3.5 cores.
+  The cap, not the droplet size, was the real limit: the container sat pegged at
+  ~197% of two cores during worldgen, so the resize alone would have bought
+  nothing. [#12]
+
+## 2026-08-06
+
+### Added
+- **Terralith 2.5.4** worldgen. Server-side only, so no pack re-import. Affects
+  newly generated chunks only; explored terrain is unchanged and there is a
+  visible seam where old meets new. [#11]
+
+### Security
+- Legion runner pinned to a full commit SHA rather than a tag. [#10]
+
+## 2026-08-02
+
+### Added
+- Server icon for the multiplayer list. [#7]
+- Website: privacy policy, full SEO, and a committed test suite gating both.
+
+### Changed
+- Renamed from "Safe Kids Server" to **EduCraft**. The old MOTD advertised to
+  every internet-wide scanner that children play here, which is precisely the
+  audience not wanted. Safety comes from the whitelist and online-mode, not the
+  label.
+- Every mod pinned to an immutable Modrinth version URL. `MODRINTH_PROJECTS`
+  resolved five mods **by name**, meaning any restart could silently swap in
+  whatever upstream had published, including a compromised build, with no
+  commit and no notification.
+
+### Removed
+- **MythicalAC anticheat**, after it kicked a whitelisted player for opening a
+  door. No config file, no ops exemption, no server-side logging, so nothing
+  could be tuned. Do not re-add an anticheat without all three. [#9]
+
+### Security
+- Pull-based GitOps deploy: the droplet polls GitHub, verifies every CI check
+  passed, backs up, rebuilds, health-checks and rolls back on failure. Nothing
+  external needs to reach in, which is what later allowed public SSH to close.
+  [#5]
+- Public SSH closed to everything but DigitalOcean console ranges. `specs/0004`.
+- Container hardened: read-only rootfs, `USER 1000:1000`, all capabilities
+  dropped, `no-new-privileges`, pids capped, BlueMap rebound to localhost.
+- auditd with 27 rules, persistent journald, fail2ban with sshd and recidive
+  jails.
+- Malware audit: all 26 mod jars verified against Modrinth published hashes,
+  26/26 clean, no fractureiser IOCs, no persistence, no C2. `specs/0003`.
+
+## 2026-04-16
+
+### Added
+- Initial server, backup policy and Forge 1.20.1 modpack.