chore: tighten markdownlint, fix lint issues #43

Job	Run time
Linux Release (FluxGraph ON, strict)	1h 41m 38s
Linux Release (FluxGraph OFF, strict)	12m 23s
Python Type Checking (mypy)	16s
Windows Release (FluxGraph ON, strict build)	1h 12m 51s
Python Linting (ruff)	16s
Windows Release (FluxGraph OFF, strict)	18m 29s
	3h 25m 53s

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