Reject C# continuation lines as function declarations

[Widthdom]

Summary

The C# declaration scanner treats non-declaration continuation lines as functions in two current shapes: one multiline LINQ invocation creates six definitions of GetIndexedLanguageCount, and multiline method-parameter continuations create functions named out or params.

Audit IDs: G-02 and P-01. Reproduced on v1.40.3 at 404db09489c305f17d94f37026e00564d3ac527a.

Existing issue relationship

These are current regressions of closed #496 (multiline call arguments becoming phantom functions) and closed #4413 (multiline out parameter continuations becoming functions). Reference both prior fixes when implementing.

Expected behavior

Only syntactically eligible declaration starts may enter the method/local-function parser. Invocation arguments and parameter continuation lines must not create symbols.

PR scope

Both reproductions share the C# declaration/expression-boundary scanner and belong in one PR. Static-lambda and reference-extraction findings remain separate.

Implementation guide for Codex 5.6 sol xhigh

• Add minimal fixtures for multiline fluent/LINQ calls and multiline declarations containing out, ref, in, and params.
• Track parenthesis/statement/declaration context before applying method patterns; do not use token-specific skips for the observed names.
• Verify real multiline methods, constructors, delegates, and local functions still index with correct ranges and containers.
• Add exact CLI symbols regressions plus extractor tests, run full net8/net9, and add a bilingual changelog fragment referencing C#: local variable initializers and multiline call arguments can be misclassified as phantom function definitions (content, FromSeconds) #496 and Prevent C# parameter modifiers from becoming symbols or references #4413.

Acceptance criteria

• The invocation yields one real definition, not six call-expression definitions.
• No parameter continuation creates an out/params function.
• Valid multiline declarations remain unchanged.

[Widthdom]

Work has started on branch fix-issue4831. I will address the C# continuation-line declaration regressions described in this issue, add focused extractor and CLI regression coverage, and preserve valid multiline declarations.