Bump version to 0.20.0 and add changelog

docs/CHANGELOG.md

@@ -0,0 +1,76 @@
+# Changelog
+
+All notable changes to `planet` are documented here.
+
+This project follows the repository versioning rule:
+
+- `feature` -> `+0.1.0`
+- `bugfix` -> `+0.0.1`
+
+## 0.20.0
+
+Released: 2026-03-26
+
+### Highlights
+
+- Stabilized the Earth big-screen module for longer-running sessions.
+- Fixed satellite orbit generation by correcting TLE handling end to end.
+- Added a reusable backend TLE helper and exposed `tle_line1 / tle_line2` to the Earth frontend.
+
+### Added
+
+- Added a dedicated Earth module remediation plan in [earth-module-plan.md](/home/ray/dev/linkong/planet/docs/earth-module-plan.md).
+- Added backend TLE helpers in [satellite_tle.py](/home/ray/dev/linkong/planet/backend/app/core/satellite_tle.py).
+- Added backend support for returning `tle_line1` and `tle_line2` from the satellite visualization API.
+
+### Improved
+
+- Reworked the Earth module lifecycle with cleaner init, reload, and destroy paths.
+- Improved scene cleanup for cables, landing points, satellite markers, and related runtime state.
+- Reduced Earth interaction overhead by reusing hot-path math and pointer objects.
+- Switched satellite animation timing to real delta-based updates for more stable motion.
+- Reduced fragile global-state coupling inside the legacy Earth runtime.
+
+### Fixed
+
+- Fixed white-screen risk caused by iframe cleanup behavior in development mode.
+- Fixed incorrect client-side TLE generation:
+  - corrected line 2 field ordering
+  - corrected eccentricity formatting
+  - added checksum generation
+- Fixed fallback orbit issues affecting some Starlink satellites such as `STARLINK-36158`.
+- Fixed partial Earth data load failures so one failed source is less likely to break the whole view.
+
+### Notes
+
+- The Earth frontend now prefers backend-provided raw TLE lines.
+- Older satellite records can still fall back to backend-generated TLE lines when raw lines are unavailable.
+- This release is primarily focused on Earth module stability rather than visible admin UI changes.
+
+## 0.19.0
+
+Released: 2026-03-25
+
+### Highlights
+
+- Refined data collection storage and history handling.
+- Moved collected data away from several strongly coupled legacy columns.
+- Improved data list filtering, metadata-driven detail rendering, and collection workflows.
+
+### Added
+
+- Added collected data history planning docs.
+- Added metadata backfill and removal-readiness scripts.
+- Added version history tracking.
+
+### Improved
+
+- Improved datasource task tracking and collection status flow.
+- Improved collected data search, filtering, and metadata rendering.
+- Improved configuration center layout consistency across admin pages.
+
+### Fixed
+
+- Fixed several collected-data field mapping issues.
+- Fixed frontend table layout inconsistencies across multiple admin pages.
+- Fixed TOP500 parsing and related metadata alignment issues.