Quality-of-life follow-up to v0.25.0: collapse the contract-name-collision diagnostic.
The v0.25.0 collision guard logged one line per colliding function, which on a repo that vendors the same interface twice produced a wall of near-identical warnings. solflow now emits one line per colliding contract-pair (naming both source files and the count) instead of one per shared method. Detection and keep-first resolution are unchanged.