Repository creates run off the async workers (closes #335) 15d3f6f7871b

## Unreleased

- **A Diffusion bump pins the upstream's default bookmark (#332).** A bump kept the bookmark name of the pin it replaced, so a subrepo first pinned at an upstream proposal's bookmark still named it after the proposal landed and Diffusion moved the pin to the default bookmark's state; a checkout then counted the subrepo as on another bookmark. A bump now names the upstream's default bookmark, unless it keeps pinned changes that bookmark lacks.

- **Listing landed proposals is quick, and pages (#331).** `oh proposal list --state landed` on a repository with a few hundred proposals timed out: the API worked out every proposal's projected state again, landed and closed ones too. Those now come from what was recorded, and the list takes `limit` (`oh proposal list --limit N`, 30 by default), newest first.

- **A big image's push no longer fails at the last step (#341).** The hub reads a whole image before it accepts the manifest, which on a busy disk outlasted `flow rootfs push`'s wait. The image could then be kept but never offered, and a retry read it all again. The hub now finishes and records the image even if the sender gives up, and a manifest it already keeps is recorded without reading the image again.

    if db::repos::get(&app.db, &name.owner, &name.name).await?.is_some() || app.repos.exists(&name) {

        return Err(ApiError(StatusCode::CONFLICT, "that repository exists".into()));

    }

    let row = db::repos::create(&app.db, &name.owner, &name.name, &body.description, body.visibility).await?;

    db::accounts::audit(&app.db, Some(me), "repo.created", &name.to_string(), "api").await.ok();

    Ok((StatusCode::CREATED, Json(repository(&app, &row))))

    let Some(name) = found else { return Err(bad("No free drop id was found; try again.")) };

    let mut repo_id = [0u8; 16];

    rand::RngCore::fill_bytes(&mut rand::rngs::OsRng, &mut repo_id);

    let id = name.drop_id().unwrap_or_default().to_string();

    let row = match db::repos::create_drop(&app.db, &account.username, &id, title, description, visibility(secret)).await {

        Ok(row) => row,

        })

    }

    /// Create an empty, unbound bare repository whose objects and

    /// operation log are kept in the store at `url` (oxygenhub#96); the

    /// store's credentials must already be known to the opener.

        .ok();

        return Ok(Redirect::to(&name.url()).into_response());

    }

    db::repos::create(&app.db, &name.owner, &name.name, f.description.trim(), visibility)

        .await

        .map_err(|e| Error::from_db(shell.clone(), e))?;