Dedupe Citations by URL — Command, Modal, and URL-Normalizing Service for Consolidating Multi-Source Research Pastes

New 'Dedupe Citations by URL' command for the workflow where the same article gets cited under multiple hex IDs because research from Perplexity / Google AI / Claude was pasted into the same file across a session. The service finds reference-section entries that share an article URL (after normalizing host case, fragment, and tracking params), groups them, and rewrites the file so each unique URL ends up with exactly one canonical hex ID. The modal lists groups in document order with per-occurrence line links, default-checked checkboxes per group so the user can opt out of any false-positive match, and a single 'Apply Dedup' button that writes through app.vault.modify.