feat(examples): add examples-resolve tool

[Timothee Guerin (timotheeguerin)]

Part of the Unified Examples Format epic (#4831), tracking #4834.

Stack

• feat(examples): add examples.yaml JSON schema and examples-validate tool #4908 — examples.yaml schema + examples-validate (base)
• feat(examples): add examples-migrate tool #5120 — examples-migrate
• This PR → examples-resolve (base: examples-migrate)

Top of the stack — review/merge after the two PRs below it. Targets examples-migrate, not main.

What

Adds the examples-resolve tool + examples-resolve CLI to @azure-tools/typespec-azure-examples, which resolves the applicable example for each operation at a target API version.

• Per lineage, selects the entry with the greatest since <= target (base entry applies from the earliest version), using the linear service.yaml version order.
• Materializes the {api-version} placeholder to the target version.
• Errors on an unknown target version; omits lineages with no applicable entry.

Tests added (vitest); tsc, oxlint, prettier clean.

[microsoft-github-policy-service]

Hi @Timothee Guerin (@timotheeguerin). Your PR has had no update for 14 days and it is marked as a stale PR. If it is not updated within 14 days, the PR will automatically be closed. If you want to refresh the PR, please remove the stale label.