v26.10.0

Plugin package version 26.10.0. The mariadb-shell MCP server floor
(MARIADB_SHELL_VERSION) stays at 26.9.5 across all ten plugins: it did
not move in this release, and 26.9.5 is still the newest mariadb-shell
release. From this release on, the plugin version no longer follows
mariadb-shell's version numbers; the floor moves only when a newer
shell is required.

Pi: the dev plugin now requires Pi 1.0 or later. Its extension
registers the mariadb MCP server with Pi's built-in MCP support, so
pi install is the whole setup, and Pi exposes the tools through
codemode by default. The pi-mcp-adapter dependency, the
/mariadb-mcp-setup command and scripts/setup-pi-mcp.sh are removed.
pi-mcp-adapter replaces Pi's built-in MCP support, so remove it with
pi remove npm:pi-mcp-adapter and turn the built-in mcp back on in
pi config.

Skills were re-vendored from mariadb-docs at 8781534, with no skill
changes; the contributor skills from mariadb-shell are unchanged at
938d473. Counts stay at 85 dev, 47 sql and 3 contributor skills.

See each plugin's CHANGELOG.md [26.10.0] section for details.