docs(changelog): document 02.53.00–02.55.00 and pending remote-storage removal [skip ci]

Populate the empty CI-generated version sections and dedupe headers:
- 02.53.00: short-name branding
- 02.54.00: per-profile retention enforcement, Purge button fix, manifest naming convention
- 02.55.00: installer licensing + install-completion pattern
- Unreleased: legacy single-remote storage removal (#204)

Claude-Session: https://claude.ai/code/session_01WbGBN9VyRK61zczYWcCQ2i

CHANGELOG.md

@@ -1,14 +1,55 @@
 # Changelog
+
+All notable changes to this project are documented in this file. The format is
+based on [Keep a Changelog](https://keepachangelog.com/); versions use
+zero-padded `MAJOR.MINOR.PATCH`.
+
 ## [Unreleased]
 
 ## [02.55.00] --- 2026-07-04
 
-## [02.55.00] --- 2026-07-04
+### Removed
+- Legacy single-remote storage: the per-profile `remote_storage` column and all
+  FTP/SFTP/S3/Google Drive credential columns. Remote destinations are now sourced
+  exclusively from the `#__mokosuitebackup_remotes` table.
+- Orphaned `SftpPath` form field and the `ajax.browseSftpDir` endpoint (leftovers
+  of the removed single-SFTP path picker).
 
-## [02.55.00] --- 2026-07-04
+### Changed
+- Package installer script adopts the standard licensing and install-completion
+  pattern: the download key is preserved across updates (backed up in preflight,
+  restored in postflight), an "installed successfully" notice shows on install and
+  update, and the license-key prompt shows on fresh install only.
+- Akeeba import no longer copies legacy remote settings onto the profile; re-add
+  remote destinations on the profile's Remote tab after importing.
 
-## [02.55.00] --- 2026-07-04
+### Fixed
+- Schema migration `02.52.25.sql` uses plain `DROP COLUMN` (portable to both
+  Oracle MySQL 8.x and MariaDB) instead of the MariaDB-only `DROP COLUMN IF EXISTS`.
 
 ## [02.54.00] --- 2026-07-04
 
-## [02.54.00] --- 2026-07-04
+### Added
+- Per-profile backup retention is now enforced. After each backup, completed
+  backups older than `retention_days` or beyond the newest `retention_count`
+  copies are pruned, along with their archive and log files (`0` = unlimited for
+  either rule). The retention fields are now shown on the profile editor's
+  Archive tab.
+
+### Fixed
+- "Purge Old Backups" toolbar button now opens the purge modal under the Joomla 6
+  Atum toolbar (it was bound to markup the toolbar no longer renders).
+
+### Changed
+- All Joomla package manifests hardcode their titles and descriptions (no language
+  strings), and `<name>` follows the `Type - Name` convention (e.g.
+  `Component - MokoSuiteBackup`, `Module - MokoSuiteBackup - cPanel`).
+
+## [02.53.00] --- 2026-07-04
+
+### Added
+- `COM_MOKOJOOMBACKUP_SHORT` short-name language constant.
+
+### Changed
+- Admin views and the administrator sidebar menu use the short "Backup" name
+  (e.g. "Backup: Dashboard", "Backup: Records").