FPM-588: Autogenerate flag values

[richjam]

Background

Previously, registering a flag system required supplying explicit power-of-2 integers for each category, e.g:

tf.register_flag_system("qc", {"OUT_OF_RANGE": 1, "SPIKE": 2, "LOW_BATTERY": 4})

This PR allows a list of strings to be passed instead, with bit values assigned automatically:

tf.register_flag_system("qc", ["OUT_OF_RANGE", "SPIKE", "LOW_BATTERY"])

The list is sorted before values are assigned, ensuring the same set of names always produces the same mapping regardless of input order. Passing None (now the default) or an empty list produces a minimal flag system with a single FLAGGED member at value 1.

Main changes

• flag_manager.py - extended FlagSystemType and added list/None handling in register_flag_system
• base.py - updated TimeFrame.register_flag_system signature and docstring to match
• test_flag_manager.py - tests for list input, sort consistency, empty list default, None default, and duplicate name error

Note

• Documentation will be modified in another PR