Release 0.10.0

A privilege-escalation fix in the Windows installer, the multi-site portability
work, and a documentation and API surface that a second site can rely on.

The installer created C:\shopdb-flask, C:\Python314 and C:\MySQL84 without
breaking inheritance from the drive root, whose default DACL grants
Authenticated Users an inherit-only Modify. Two files inside those roots are
executed by someone else - shopdb-admin.ps1 self-elevates, and instance
config.py is loaded unconditionally by the app - so any logged-on user could
replace either and wait. Verified fixed as SYSTEM in the Windows 11 VM against
the shipped functions.

Contract 0.19.0 is breaking: get_dashboard_widgets returns data and shape, not a
component name. The change itself shipped earlier without a bump, with the
contract docs still teaching the dead shape; both are corrected.

The version and the changelog are the release; the detail is in the entry.

shopdb/__init__.py

@@ -63,7 +63,7 @@ __contract_version__ = '0.19.0'
 # plugin-contract version above are distinct series with independent
 # bump rules. Not part of the shopdb.api contract surface, so it is
 # not re-exported there.
-__version__ = '0.9.0'
+__version__ = '0.10.0'
 
 
 def create_app(config_name: str = None) -> Flask: