# Task 06G4W63545T3RV8SSKGKN11B3G

Run a single named check with --only

- Project: test-e2e
- Source: gitea:test-e2e/26
- Priority: 0

## Instructions

Give scripts/orchestra_e2e_healthcheck.sh a `--only <name>` flag that runs a single named check instead of all ten, then prints the usual success line.

Behaviour:

- `--only repo_root_readable` runs that check alone and exits 0 when it passes.
- `--only nonsense` prints `unknown check: nonsense` on stderr and exits 2.
- `--only` composes with `--summary`, `--json` and `--quiet`, each keeping its current shape over the single result.
- Without `--only`, every existing flag behaves exactly as it does today.

Plan this as FIVE phases:

1. A helper that resolves a name to a check function and reports whether the name is known.
2. Flag parsing for `--only <name>`, with the unknown-name refusal and exit 2.
3. Running the single resolved check and recording its result through the existing results state.
4. Composition with `--summary` and `--json`.
5. The usage text in `--help`, and assertions in scripts/test_healthcheck.sh for each behaviour above.

## Work one phase at a time

Implement phase N, request its verification, and only then begin phase N+1. Do not write the whole change first and verify the phases afterwards.

## Every phase carries both kinds of check

This is a hard requirement of this task. Each phase must have at least one automated check from the policy below. Each phase must also have at least one manual check, confirmed by a human reading the printed output. Orchestra runs the automated ones. A human owns the manual ones, and the phase is not finished until that human signs it off.

## Verification policy for this project

Only two commands may appear on a run: line, exactly:

- ["bash", "-n", "<path>"]
- ["bash", "scripts/orchestra_e2e_healthcheck.sh"]

Anything else is refused when you seal the plan.

## Research first

Establish at least three findings with distinct confidence: at least one fact, one inference, one assumption.

## Handoff behaviour

Behave normally. If Orchestra asks you to write a handoff report, write it and stop.

Acceptance:
- `--only <name>` runs exactly one check.
- An unknown name exits 2 with a message on stderr.
- `--only` composes with `--summary`, `--json` and `--quiet`.
- Every existing flag is unchanged when `--only` is absent.

## Completion

Run the configured quality gate. When the task is ready for the worker to verify and deliver, create `.orchestra/done`. Do not write a prose completion report.

This file is immutable for the lifetime of the task (§6.2) — its hash is
carried in every handoff and re-verified on every pickup. Do not edit it.