fix(phpstan): address phpstan identified type errors and refactor code

See merge request !43

Refactor several PHP files to fix type-related errors and potential crash scenarios. These include:
- Checking if a method exists before attempting to call it
- Providing alternatives for default values where a procedure may not exist
- Ensuring variables are initialized properly regardless of whether procedures execute successfully
or not
- Casting return types to match the return type in function comments
- Other significant changes to improve overall code stability and predictability.

Related: #149

feat: add new children list template -> gallery overlay

See merge request !42

Related: pcsg/kunden/bedachungen-heinen.de-template#10

fix: automatic conversion of false to array is deprecated

See merge request !41

Next 2.x

See merge request !40

Next 2.x

See merge request !39

fix: cleanup internal instance array if brick is saved

See merge request !38

Next 2.x

See merge request !36

Add QUIQQER Tooling

See merge request !33

Next

See merge request !32

Dev

See merge request !31

Next

See merge request !30

fix: quiqqer/quiqqer locale and paths adapted to quiqqer/core

See merge request !29