v26.10.6

Plugin package version 26.10.6. The mariadb-shell MCP server floor
(MARIADB_SHELL_VERSION) moves from 26.10.3 to 26.10.4, the newest
mariadb-shell release (published 2026-10-24). An install already at or
above 26.10.4 is used as-is; only a machine below it fetches anything.

Every plugin's LICENSE now names the bundled VS Code extension by its
current name, MariaDB Shell for VS Code.

Skills were re-vendored from mariadb-docs at 62ef6fe and from
mariadb-shell at b074605; no skill content changed. Counts stay at 85
dev, 47 sql and 3 contributor skills.

See each plugin's CHANGELOG.md [26.10.6] section for details.