Quote-shelf connect link and provider-evidence prefill (deferred from #212)

[holden]

Deferred from #212, Build 2 (PR stacked on #218). This issue owns the part of #212's named discovery path that does not exist on main:

a quotation from a provider with identity_record/1 on a word's Quotes shelf → its card's connect link → ConnectionLive with subject, sense, evidence_revision and evidence_locator prefilled → propose/6 → …

What main has (checked at c6bd882)

• The only shelf link to /connect is components/culture.ex:1580-1588. It is guarded by connect_path/1 (culture.ex:1617-1636), which needs a sense_id. Only artwork catalog-corpus items carry one (artworks.ex:248).
• The quote card (culture.ex:872) has no connect link, and a Discovery.Result has no sense.
• ConnectionLive preselects evidence only from an artsy record that materialized the subject (connection_live.ex preselected_evidence/3).

What #212's Build 2 already provides

• ConnectionLive records metadata["from_result"] and metadata["provider"] for a /connect?…&from_result=<id> link. It keeps them only when the result is about the prefilled subject, and reads the provider from the result's run.
• Examples.Provenance names where the nomination was found.
• A test proves the rest of the path from the form onwards: the published exemplar reads back after Discovery.purge_results/1, with every provider off, and no second object, evidence row or claim.

What this issue adds

1. A connect link on a quote card for a result that resolved to a registry object (Wikiquote's content/quotation), shown to internal contributors only, like the catalog link. It carries subject and from_result. The contributor chooses the sense in the form, because a result has none.
2. The provider's record as evidence. ConnectionLive preselects the result's source_record_id → current revision as supporting evidence. It verifies this server-side from the result row, not from the URL, and widens preselected_evidence/3 beyond artsy only for this verified case.
3. The end-to-end test Examples in the curated opening: an exemplar item kind, one provenance projection, and the manual proof (integration under #193) #212 named: click the quote card's link → submit → accept → compose the exemplar with its pinned words → publish → purge the result → read back with every provider off. The evidence names the Wikiquote record, and nothing is duplicated.

Out of scope

• Results with no registry object: minting them is Exemplars: people, works and media as attributed examples of a meaning — nomination, the why, votes, ranking and the reverse view on a person's page #105 step 5.
• Other shelves.