Package for public GitHub release

Add open-source scaffolding and CI; remove Claude-specific dev notes from the
published tree.

- Remove CLAUDE.md from tracking (kept locally, now git-ignored).
- CHANGELOG.md (Keep a Changelog; v1.0 → v1.1.1).
- SECURITY.md (private vuln reporting + operator guidance).
- CONTRIBUTING.md (dev setup, conventions, PR flow).
- .github/: bug + feature issue templates, PR template.
- .github/workflows/ci.yml: byte-compile, validate example config, docker build.
- .github/workflows/release.yml: on a version tag, publish a multi-arch
  (amd64 + arm64) image to GHCR.
- README: license/release/CI badges, prebuilt-image (GHCR) run instructions,
  and a corrected Python-version note (3.9–3.11; netifaces caveat).

Badges and image names use an `OWNER` placeholder to replace with the GitHub
namespace after the repo is created.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -0,0 +1,48 @@
+# Changelog
+
+All notable changes to this project are documented here. The format is based
+on [Keep a Changelog](https://keepachangelog.com/), and this project adheres to
+[Semantic Versioning](https://semver.org/).
+
+## [1.1.1] - 2026-06-10
+
+### Added
+- `/health` endpoint (status, version, receiver/flight counts) plus a Docker
+  `HEALTHCHECK`.
+- `ADSBIT_CONFIG` environment variable to override the config file path.
+
+### Changed
+- Docker first-run now works with no manual steps: `config.json` is auto-seeded
+  from `config.json.example` by `docker-entrypoint.sh` and persisted on a
+  `./data` directory mount (removing the single-file bind-mount footgun).
+- Network auto-scan skips subnets larger than `/20` (e.g. a Docker bridge
+  `172.17.0.0/16`) so discovery no longer stalls startup on Docker hosts.
+- `SIGTERM`/`SIGINT` (`docker stop`, `systemctl stop`) shut down cleanly
+  without a stack trace.
+
+## [1.1.0] - 2026-06-09
+
+### Added
+- In-app pixel editor for sprites (admin → Sprites → EDIT): pencil, eraser,
+  color picker, fill bucket, line/rectangle/ellipse shapes, rectangular
+  select with move/cut/copy/paste, reference-image overlay, brush size &
+  opacity, custom + recent palettes, zoom/pan, grid, undo/redo.
+- Receiver health dashboard: live per-receiver status (receiving / no data /
+  unreachable), connection testing, a select → save → apply flow, selectable
+  scan results, and a per-interface scan selector.
+- Version surfaced at startup, via `GET /api/config`, and in the admin header.
+
+### Fixed
+- Server crash when restarting receiver connections: cancelled receiver tasks
+  no longer tear down the main event loop.
+
+## [1.0] - 2026-01
+
+### Added
+- Initial release: retro SNES-style side-view ADS-B flight tracker with custom
+  pixel-art sprites, directional backgrounds, weather, sun/moon, admin panel,
+  first-run setup wizard, and Docker/Podman support.
+
+[1.1.1]: https://github.com/OWNER/ADS-Bit/releases/tag/v1.1.1
+[1.1.0]: https://github.com/OWNER/ADS-Bit/releases/tag/v1.1.0
+[1.0]: https://github.com/OWNER/ADS-Bit/releases/tag/v1.0