refactor(metadata): use snake_case for all catalogue parameter names (HF-249)

[sequba]

Context

Addresses a code-review finding on #1692: the function-metadata catalogue mixed several parameter-name conventions, which surface directly in a function-picker UI. Even closely-related functions disagreed — SUMIF used Range, Criteria, Sumrange, SUMIFS used Sum_Range, Criterion_range1, Criterion1, AVERAGEIF used Range, Criterion, Average_Range — mixing Title-case, snake_Case, and run-on tokens.

This normalizes every FunctionDoc parameter name to snake_case so the catalogue is internally consistent.

What changed

• All 172 unique parameter names across the 13 categories/*.ts files are now snake_case (lowercase words joined by _, camelCase/acronym boundaries split, separators unified, trailing digits kept attached: Number1/Number_1 → number1).
• Run-on tokens the docs left unsplit are segmented so siblings agree: Sumrange → sum_range (matches SUMIFS), Searchcriterion → search_criterion (matches VLOOKUP/HLOOKUP), plus logical_value, date_string, time_string, start_date, minimum_length, lower_bound, upper_bound, number_x, number_y.
• The migration generator (scripts/hf249-migrate-function-docs.ts) now emits snake_case via a shared, exported toSnakeCase helper (+ a small segmentation table), so a future regeneration stays consistent. Its main() is guarded with require.main === module so the helper can be imported without side effects.
• Not touched: parameter descriptions, examples, documentationUrl, categories, short descriptions, ordering. Custom-function positional names (Arg1, Arg2, …) are unchanged — they are a documented, self-consistent placeholder for user functions that ship no metadata (see open question below).

How did you test your changes?

• tsc --noEmit — clean.
• eslint on the changed files — 0 errors.
• test/smoke.spec.ts — 4/4 pass.
• Ad-hoc runtime checks against the built API:
  • every catalogue and getFunctionDetails parameter name matches ^[a-z][a-z0-9]*(_[a-z0-9]+)*$;
  • names are unique within each function (no collisions introduced by the transform);
  • getAvailableFunctions/getFunctionDetails list↔details parity still holds;
  • SUMIF & SUMIFS both expose sum_range; MATCH & VLOOKUP both expose search_criterion;
  • custom-function details still report Arg1, Arg2.
• Ran the generator to confirm it produces identical parameter names to this hand-applied transform (the only regen deltas are unrelated pre-existing drift — alphabetical re-sorting of manually-added HSTACK/XIRR, the hand-authored SUM/SUMIF fields, and a stale TEXT description — so the regen output was discarded).

Types of changes

• Breaking change (a fix or a feature because of which an existing functionality doesn't work as expected anymore)
• New feature or improvement (a non-breaking change that adds functionality)
• Bug fix (a non-breaking change that fixes an issue)
• Additional language file, or a change to an existing language file (translations)
• Change to the documentation

Related issues:

1. Follow-up to Function metadata API: getAvailableFunctions / getFunctionDetails (HF-249) #1692 (HF-249); targets that branch.

Notes for reviewers

• Paired tests: the private test suite (hyperformula-tests#14) asserts specific parameter names (e.g. SUMIF params); those expectations need updating to the new snake_case names.
• Open question — custom functions: the request was "snake_case for all param names". I scoped this to the catalogue and left the runtime custom-function placeholders as the documented Arg1/Arg2. If you'd also like those lowercased (arg1/arg2), it's a 1-line change in buildCustomFunctionDetails plus a custom-functions.md wording update — say the word.
• Segmentation calls (sumrange→sum_range, etc.) are the only editorial decisions here; everything else is mechanical.

  

[qunabu]

Task linked: HF-249 HF function documentation available via API

[github-actions]

Performance comparison of head (07161a0) vs base (18d4246)

                                     testName |   base |   head | change
------------------------------------------------------------------------
                                      Sheet A | 486.32 | 504.74 | +3.79%
                                      Sheet B | 157.63 | 163.53 | +3.74%
                                      Sheet T | 146.84 | 144.89 | -1.33%
                                Column ranges | 479.49 | 481.36 | +0.39%
Sheet A:  change value, add/remove row/column |  16.99 |  17.94 | +5.59%
 Sheet B: change value, add/remove row/column | 146.24 | 145.13 | -0.76%
                   Column ranges - add column | 151.86 |  164.9 | +8.59%
                Column ranges - without batch | 468.23 | 480.48 | +2.62%
                        Column ranges - batch | 119.88 | 124.31 | +3.70%

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.61%. Comparing base (18d4246) to head (07161a0).
⚠️ Report is 1 commits behind head on feature/hf-249-function-metadata-api.

Additional details and impacted files

@@                           Coverage Diff                            @@
##           feature/hf-249-function-metadata-api    #1709      +/-   ##
========================================================================
+ Coverage                                 96.42%   96.61%   +0.19%     
========================================================================
  Files                                       192      192              
  Lines                                     15585    15585              
  Branches                                   3447     3447              
========================================================================
+ Hits                                      15028    15058      +30     
+ Misses                                      557      527      -30     

Files with missing lines	Coverage Δ
.../functionMetadata/categories/array-manipulation.ts	100.00% <ø> (ø)
...nterpreter/functionMetadata/categories/database.ts	100.00% <ø> (ø)
...reter/functionMetadata/categories/date-and-time.ts	100.00% <ø> (ø)
...rpreter/functionMetadata/categories/engineering.ts	100.00% <ø> (ø)
...terpreter/functionMetadata/categories/financial.ts	100.00% <ø> (ø)
...rpreter/functionMetadata/categories/information.ts	100.00% <ø> (ø)
...interpreter/functionMetadata/categories/logical.ts	100.00% <ø> (ø)
...unctionMetadata/categories/lookup-and-reference.ts	100.00% <ø> (ø)
...nctionMetadata/categories/math-and-trigonometry.ts	100.00% <ø> (ø)
...er/functionMetadata/categories/matrix-functions.ts	100.00% <ø> (ø)
... and 3 more

... and 5 files with indirect coverage changes

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