QDoc: Resolve explicit QML dot-path links

The template link resolver only attempts QML dot-path lookup when a
link explicitly requests the QML genus, and its type-only lookup
cannot resolve ordinary property and enum references. Authored links
such as Type.property therefore become plain text with false warnings.

Pass explicit-versus-automatic link intent and authored search criteria
to scoped lookup. Resolve eligible names through shared QML discovery.
Use the enclosing QML type for member-local module disambiguation and
search the selected physical tree directly when a scope is supplied.
Keep forced non-QML genus, URLs, filenames, titles and automatic
references on their existing paths, and validate fragments on the
newly resolved targets.

Cover type and member contexts, competing logical and physical
modules, forced genus, real imported-tree scopes, fragments and the
braced multiword title control in both template formats. Also cover
shared attached-property selection, chains and overloaded methods.
Keep legacy output and its intentional member-context diagnostics as
controls. Import-alias interpretation is a separate follow-up.

Task-number: QTBUG-137279
Pick-to: 6.12
Change-Id: I82d027fa98c14801784e1b7d46b2f9d4add71dba
Reviewed-by: Topi Reinio <topi.reinio@qt.io>