fix: distinguish duplicate CDecay statements

[jpwgnr]

Summary

This fixes two CDecay validation issues discovered while enabling the
DecayLanguage pre-commit hook in LHCb's DecFiles repository:

• DecFiles !2775
  exposed files that define the same particle with both Decay and CDecay.
• DecFiles !2776
  exposed repeated CDecay statements, which were not reported separately.

DLW003 is now named decay-cdecay-conflict, matching its existing meaning.
The new DLW006 duplicate-cdecay diagnostic reports repeated CDecay
statements, and the parser retains only one statement so it cannot create
duplicate charge-conjugate decay trees.

The warning categories, CLI output, tests, and documentation have been updated.

Validation

• Full test suite: 380 passed, 1 skipped.
• Full pre-commit suite passed.
• Verified against the affected DecFiles corpus.

Let me know what you think @eduardo-rodrigues.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.62%. Comparing base (9ee93c3) to head (82289c5).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #613      +/-   ##
==========================================
+ Coverage   97.60%   97.62%   +0.02%     
==========================================
  Files           6        6              
  Lines        1209     1222      +13     
==========================================
+ Hits         1180     1193      +13     
  Misses         29       29              

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[eduardo-rodrigues]

Hello @jpwgnr, thank you for the speedy action given our discussions. I will check more in detail as soon as possible. For now I wanted to make an annoying comment to keep some symmetry, which I like. Given that the hook is so new and only LHCb-via-you is using it for now, I think we can still afford a change of "order" in diagnostics to have the following table, which I find nicer - we can quickly release a patch version:

| DLP001 | parse-error | The file could not be read or parsed by DecFileParser. |
| DLW001 | duplicate-decay | A particle has multiple Decay blocks; only the first is retained. |
| DLW002 | duplicate-cdecay | A particle has multiple CDecay statements; only the first is retained. |
| DLW003 | decay-cdecay-conflict | A particle is defined with both Decay and CDecay; CDecay is ignored. |
| DLW004 | missing-cdecay-source | A CDecay statement has no corresponding Decay source. |
| DLW005 | self-conjugate-cdecay | A CDecay statement targets a self-conjugate particle. |
| DLW006 | missing-copydecay-source | A CopyDecay statement references a missing Decay source. |
| DLW999 | parser-warning | An otherwise unclassified warning was emitted by DecFileParser. |

WDYT?

[eduardo-rodrigues]

Hello @jpwgnr, do let me know if you need help here, and I will try and make some time. I see that is now necessary for the LHCb work using the hook to be finalised and put into production.

[jpwgnr]

Hi @eduardo-rodrigues,
I adressed both of your requests.
Please give it another careful look, not that I missed anything.

[eduardo-rodrigues]

Super, all goods good to my eyes 👍!

Thank you. I will make a new patch release shortly so that you can go and use this in the LHCb validations.

[eduardo-rodrigues]

Hello @GiacomoXT, this new hook, see the README, may be of use as well within Belle-II for your validations. Just thought I would drop a comment for you. Greetings.

[GiacomoXT]

Thanks a lot! @vvsagar and I will impelement this in our pipeline.

[eduardo-rodrigues]

Thanks a lot! @vvsagar and I will impelement this in our pipeline.

Top. Drop a line with feedback or a all-working-fine ... Thanks.