crates/traverse-registry: emit resolve usage-telemetry event (Spec 015)

[enricopiovesan]

Summary

Instrument crates/traverse-registry's resolution path to accept an optional UsageTelemetrySink (from traverse-contracts) and invoke it with a resolve event on successful version resolution, per Spec 015 (specs/015-runtime-usage-telemetry-resolve-hook).

Why

Spec 015 authorizes this as the one real behavior change decision 47 (docs/decision-log.md entry 47) requires of this extracted crate. Without it, traverse-framework/traverse's Spec 088 has no real resolve counter — only the execute counter (implemented entirely in that repo's traverse-cli) would ever fire.

Depends on

• Spec 015 approved (PR spec(015): authorize resolve-hook behavior change to crates/traverse-registry #144)
• traverse-framework/traverse#927 (UsageTelemetrySink trait published in traverse-contracts)

Blocked by

• traverse-framework/traverse#927 must ship and publish a new traverse-contracts version before this crate can bump its pinned dependency (Cargo.toml's workspace.dependencies.traverse-contracts) and implement against the real trait.

Definition of Done

• crates/traverse-registry's public resolution API accepts an optional UsageTelemetrySink parameter; omitting it produces byte-identical behavior to today.
• A successful resolution with a sink supplied invokes it exactly once with the correct namespace/id@version and nothing else.
• A failed/ambiguous resolution never invokes the sink.
• No new dependency beyond the version-bumped traverse-contracts (cargo tree -p traverse-registry shows no new crate).
• New patch/minor version of traverse-registry published per this repo's crate-publish pipeline (spec 010).

Validation

• Unit tests for SC-001 through SC-004 in Spec 015.
• cargo test -p traverse-registry passes.
• cargo tree -p traverse-registry reviewed manually to confirm no new dependency.