chore(modeldb): refresh OpenRouter catalog snapshot and align docs

[vadimcomanescu]

Summary

Refreshes the pinned OpenRouter model catalog and aligns documentation with current catalog behavior.

Problem

Pinned catalog snapshots drift over time, causing stale model metadata and confusing operator expectations.

Why This Change

Catalog refreshes should be explicit, reproducible, and accompanied by docs updates when behavior notes change.

What Changed

• Updated pinned OpenRouter catalog snapshot.
• Added/updated refresh script for repeatable catalog regeneration.
• Aligned attractor documentation note with current codex schema behavior.

User-Visible Behavior

• Model catalog data reflects current provider snapshot.
• Documentation better matches observed runtime behavior.

Risk

• Catalog updates can change model availability expectations.
• Mitigation: snapshot update is isolated, test-covered, and script-backed.

Validation

• gofmt and go vet ./...
• go test ./internal/attractor/modeldb -count=1