Regression discovered during development of PyQt v6.7.0

[philthompson10]

The development of PyQt v6.7.0 is the first major test of metasip since its public release. This issue captures the regressions discovered during that process.

• crash when resetting the workflow
• crash when scanning a header directory
• a scanned header directory does not expand to show files that need parsing
• crash when parsing a header file
• slots and signals are not recognised as existing methods
• crash when adding a new header file to a module
• drag and drop doesn't work
• some new API element are not initialised as Unchecked.