clear module cache on LSP save to avoid polluting context

[hexdae]

Note

Medium Risk
Touches evaluation-session caching and LSP save/viewer paths; mistakes could lead to stale/incorrect diagnostics or state, though scope is limited to editor workflows.

Overview
Prevents cross-file contamination in the shared evaluation module_tree by clearing it during EvalContext::parse_and_analyze_file.

Updates the LSP to cache the computed pcb_sch::Schematic (instead of the full EvalOutput) immediately after evaluation, and reuses that schematic for viewer/getState and on_save_diagnostics, clearing the cache on failures and file close.

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[LK]

prob don't need changelog if it was introduced + fixed in same release

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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