Add Twix, MRS and PMU raw data readers

[jamesdidathing]

• Added .rda (MRS spectroscopy) format: validates the >>> Begin of header <<< marker and parses metadata from the text header
• Added .puls (PMU) format: validation through extension with metadata parsing from the footer section
• Added .dat (twix k-space) format: validates VB/VD/VE version (replicating same check used in twixtools), exposes measurement count, and reads protocol headers via twixtools
• Added tests for all 3 new formats using mock data

Reviewers:
Run tests and ensure they pass correctly, and review the code and logic

[codecov]

Codecov Report

❌ Patch coverage is 88.88889% with 11 lines in your changes missing coverage. Please review.
✅ Project coverage is 86.85%. Comparing base (12cfb29) to head (a154002).
⚠️ Report is 12 commits behind head on main.

Files with missing lines	Patch %	Lines
...tras/fileformats/extras/vendor/siemens/medimage.py	81.39%	8 Missing ⚠️
fileformats/vendor/siemens/medimage/twix.py	90.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main       #2      +/-   ##
==========================================
+ Coverage   86.60%   86.85%   +0.25%     
==========================================
  Files           5        8       +3     
  Lines         224      312      +88     
==========================================
+ Hits          194      271      +77     
- Misses         30       41      +11     

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[tclose]

Thanks @jamesdidathing, it looks great! Just have a few minor comments and suggestions on naming conventions

[tclose]

Re naming convention, the format of the raw data files should be consistent with the console software platform, which for the Cima X is called "Syngo MR XA". FileFormats automatically maps Python class names to "mime-like" string with _ -> . and [A-Z] -> -[a-z] so fileformats.vendor.siemens.medimage.SyngoMr_Xa_Puls -> medimage/vnd.siemens.syngo-mr.xa.puls.

[jamesdidathing]

Didn't realise this, changed them now

[tclose]

Actually, I should have written SyngoMr_Xa_Puls with the lowercase r to match the convention. Would you mind find/replacing that?

[tclose]

SyngoMr_Xa_Twix is probably a good name

[tclose]

The Cima is XA (the next version after VE). Do the twixtools support it?

[jamesdidathing]

So from what I can tell, VE and XA have the same underlying structure so it should handle correctly. It works with the example file you sent over to me, but might be worth testing with some more files?

The method name/docstring I can change too if its confusing.

[tclose]

NB: I will create a separate PR to fix the mac-os ci/cd problem

[tclose]

NB: I will create a separate PR to fix the mac-os ci/cd problem

This is done now. Could you rebase on main?