fix(browser): clear stale source-view interactions

[ShivamB25]

Summary

• Clear interaction state before replacing rendered page lines with raw source lines.
• Prevent stale focused-link, form, mouse-row, and hover-URL indexes from acting on source text.

Verification

• cargo test source_view_clears_interaction_indexes_for_replaced_lines
• cargo test
• cargo clippy --all-targets -- -D warnings

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