ADR-0004's title reads vLLM first after its amendment inverted the order

## Defect

`docs/adr/0004-vllm-first-runtime.md:1` and the `docs/adr/index.md:43` row read "vLLM as the first target runtime". The record's own amendment (2026-07-29) states the build order inverted: the GGUF backend shipped first and no vLLM pack backend exists. A reader of the index sees a runtime priority false since 2026-07-29.

## Ask

Decide how an Accepted ADR's title reads after an amendment inverts it. Options: leave the title and mark the index row, or retitle with a dated note. The ADR lifecycle on the index page does not say. Changing an Accepted ADR's title is a decision, so this is not a task.

Found on 2026-09-03 during the #484 checks (chart #481).

Read docs/adr/0004-vllm-first-runtime.md:1 and the docs/adr/index.md:43 row, then review the ADR’s 2026-07-29 amendment. Decide how an Accepted ADR title and index row should represent an inverted build order, and document the decision in the ADR lifecycle guidance; done means the stale runtime-priority wording has an agreed treatment.

Written by the indexing model from the issue text.