Implement docked variant for Drawer

[philippjfr]

• Adds a new variant="docked" option to Drawer that renders a small toggle tab on the anchored edge, allowing users to open/close the drawer without a separate button
• Adds dock_position parameter ("start", "middle", "end") to control placement of the toggle tab along the drawer edge
• Updates the reference documentation with the new variant and parameter

Details

The docked variant uses a persistent MUI Drawer under the hood but wraps it in fixed positioning with a DockedTab component. When the drawer is closed, only the tab is visible flush against the viewport
edge. When open, the tab attaches to the drawer's outer border (offset by 1px to avoid overlapping the border line) and switches its chevron direction to indicate it will close.

The dock_position parameter allows positioning the tab at the start, middle (default), or end of the drawer edge, accommodating different layout needs (e.g. placing it near a header or footer).

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 85.06%. Comparing base (85ab0a4) to head (74ef2d8).

Additional details and impacted files

@@             Coverage Diff             @@
##             main     #696       +/-   ##
===========================================
+ Coverage   71.24%   85.06%   +13.81%     
===========================================
  Files          33       33               
  Lines        3822     3823        +1     
===========================================
+ Hits         2723     3252      +529     
+ Misses       1099      571      -528     

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