fix(lsp): guard Locate against out-of-bounds ranges

[SAY-5]

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fix: A bug fix

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en: LSPClient.Locate indexes LineCounts by the LSP-provided line numbers and then slices text[start:end] without validating either. When an LSP server returns a stale or out-of-sync range (for example pylsp/jedi following imports into .venv), the line index can exceed len(LineCounts) or the offsets can be inverted, producing slice bounds out of range [13:6] and crashing the whole parse run. This adds bounds and ordering checks that return an error instead of panicking, matching the guard already present in the sibling Line method. A unit test covers the valid case and three out-of-bounds variants.
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Fixes #186

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