fix(er): support left-side numeric entity identifier 1

[Gaston202]

Disambiguate numeric token handling in ER parser so left-side entity name "1" works in relationship statements, while preserving right-side numeric entity cases from #7472.

• refine lexer lookahead for cardinality token 1
• allow ONLY_ONE token where an entity name is valid
• add regression tests for left-side forms: "1 1 to many" and "1 many to many"

Refs #7472

📑 Summary

This PR fixes an ER parser regression where the left-side entity name "1" could be interpreted as cardinality in relationship statements.

It disambiguates numeric token handling so left-side numeric entity names parse correctly, while preserving the right-side numeric entity behavior introduced in #7472.

Resolves #7472

📏 Design Decisions

• Refined lexer lookahead handling for token 1 to avoid over-greedy matching in ambiguous relationship contexts.
• Allowed ONLY_ONE in entity-name parsing context so numeric identifier "1" can be treated as an entity where valid.
• Added regression tests to cover both left-side forms:
  • 1 1 to many SomeEntity: label
  • 1 many to many SomeEntity: label

📋 Tasks

Make sure you

• 📖 have read the contribution guidelines
• 💻 have added necessary unit tests for the regression
• 📓 have added documentation. Not required for this bug fix because no new feature or syntax was introduced.
• 🦋 If this fix should be included in changelogs, generate a changeset with patch level and prefix fix:.

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commit: 2c6966b

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✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 3.33%. Comparing base (57e5f54) to head (2c6966b).

Additional details and impacted files

@@           Coverage Diff           @@
##           develop   #7598   +/-   ##
=======================================
  Coverage     3.33%   3.33%           
=======================================
  Files          536     536           
  Lines        56249   56249           
  Branches       820     820           
=======================================
  Hits          1876    1876           
  Misses       54373   54373           

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Build	Status	Details	Updated (UTC)
default (Inspect)	⚠️ Changes detected (Review)	1 changed	Apr 10, 2026, 5:36 PM