docs: simplify v2026.4.303 changelog and update entries}
- Replace detailed multi-category changelog for v2026.4.303 with condensed summary of key changes - Add entry for GitHub draft release promotion to published via API - Add bugfix entry for draft release handling (drafts not returned by tags endpoint) - Add entry for dropping armv7l (32-bit ARM) build targets due to Electron 41 incompatibility - Remove 19 lines of granular per-commit entries in favor of 3 high-level summaries