7162: add line and column numbers to parse error messages

[omkarht]

📑 Summary

Enhanced the MermaidParseError class to include line and column numbers in all parser error messages, significantly improving debugging experience. Previously, syntax errors only showed generic messages without location information. Now all diagram types (radar, pie, info, packet, etc.) display errors in the format: Parse error on line X, column Y: <error details>. Added comprehensive tests to verify error formatting and updated existing tests to match the new format.

Resolves #7162

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Latest commit: fd3fc50

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This PR includes changesets to release 2 packages

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@mermaid-js/parser	Patch
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commit: fd3fc50

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Codecov Report

❌ Patch coverage is 0% with 20 lines in your changes missing coverage. Please review.
✅ Project coverage is 3.59%. Comparing base (4261d3e) to head (fd3fc50).
⚠️ Report is 58 commits behind head on develop.

Files with missing lines	Patch %	Lines
packages/parser/src/parse.ts	0.00%	20 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           develop   #7333      +/-   ##
==========================================
- Coverage     3.59%   3.59%   -0.01%     
==========================================
  Files          474     474              
  Lines        47471   47489      +18     
  Branches       740     740              
==========================================
  Hits          1705    1705              
- Misses       45766   45784      +18     

Flag	Coverage Δ
unit	3.59% <0.00%> (-0.01%)	⬇️

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Files with missing lines	Coverage Δ
packages/parser/src/parse.ts	1.26% <0.00%> (-0.38%)	⬇️

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Build	Status	Details	Updated (UTC)
default (Inspect)	✅ No changes detected	-	Jan 21, 2026, 11:09 AM

[Copilot]

Pull request overview

This PR enhances parser error reporting so that syntax and lexer errors across Mermaid diagram types include explicit line and column information, improving debugging and aligning with the behavior requested in issue #7162.

Changes:

• Updated MermaidParseError to wrap lexer and parser errors with standardized, location-aware messages (Lexer error on line X, column Y: and Parse error on line X, column Y:).
• Added radar parser tests that validate the presence and formatting of line/column information in both lexer and parser error scenarios.
• Updated the info diagram tests to match the new error message format and added a changeset entry documenting the behavior change in @mermaid-js/parser.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
packages/parser/src/parse.ts	Centralizes error formatting in MermaidParseError to include line and column numbers for lexer and parser errors, affecting all diagram types that use the shared parser.
packages/parser/tests/radar.test.ts	Extends radar grammar tests to call the shared async parse API and assert that thrown MermaidParseError instances include line/column information and the standardized Parse error on line X, column Y prefix.
packages/mermaid/src/diagrams/info/info.spec.ts	Adjusts info diagram parser tests to assert the new lexer error message format including line and column metadata.
.changeset/slow-bees-mate.md	Records a patch-level changeset for @mermaid-js/parser describing the enhanced parser error messages for release notes.

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