feat(web): the hub's sky on Explore and the signed-out home (closes #165) 0a3b244b748f

- **Diffusion (#148, docs/diffusion.md).** When a repository that others pin as a subrepo moves on, each consumer that follows it gets a proposal moving the pin, signed by the hub, tested by the consumer's own pipeline, with the upstream's changes listed. One proposal per consumer and subrepo, kept up to date; never landed by itself. Turned on per repository (Settings › Diffusion, `PUT /repos/{owner}/{name}/diffusion`, or `follow` in `.oxymodules`), off by default; `green` waits for the upstream's run to pass. A repository's page shows who uses it and how far behind each is (Diffusion › Diffuses to, `GET /repos/{owner}/{name}/consumers`). Consumers are bumped on the bookmark their work lands on, learned from where their proposals land.

- **Diffusion in the API (#153):** `GET /repos/{owner}/{name}/diffusion` gives what a repository takes from and what it diffuses to, each with its pill, for the VS Code extension.

- **The card layout everywhere (#159–#164):** the About card's counts in its heading and its buttons centred; wider repository cards with each Diffusion row on one line; the Code button and + New project in the accent blue; proposal and issue sidebars, profile and organisation pages, search results and the wiki's sidebar as cards; every panel's and form card's heading a shaded bar.

- **Your sky (#157, docs/backgrounds.md):** a quiet, moving backdrop behind the dashboard, drawn in Rust compiled to WebAssembly: your repositories as clusters and their last 30 days (every change pushed, proposal and issue events, releases, Flow runs) as marks around them; the cursor lights and links them, and names the cluster it rests by. Settings › Appearance: Moving, Still or Off; still under reduced motion.

- **Signed-in pages are private (#158):** HTML for a signed-in viewer says `Cache-Control: private, no-store`, so no proxy or CDN serves one viewer's page to another.

- **The dashboard in cards (#155):** each section a rounded card with its heading and count in a shaded bar, your repositories a sidebar card with New in its heading.

    sort: String,

    topic: String,

    stars: std::collections::HashMap<i64, i64>,

}

impl HomePage {

const FEED_LIMIT: i64 = 40;

/// The most events Your sky reads, and how far back (docs/backgrounds.md §5).

const SKY_EVENTS: i64 = 1500;

const SKY_DAYS: i64 = 30;

/// Your sky's data (docs/backgrounds.md §5): the viewer's repositories and

        "name" => repos.sort_by_key(|r| (r.name.to_lowercase(), r.owner.to_lowercase())),

        _ => repos.sort_by_key(|r| std::cmp::Reverse(r.updated_ms)),

    }

}

/// A person's page (hub spec §6): avatar, names, bio, linked signing

        sort: "activity".into(),

        topic: String::new(),

        stars,

    })

    .into_response())

}

        .await

        .unwrap();

    assert_eq!(res.headers()[header::CACHE_CONTROL], "private, no-store");

    // The engine is served as WebAssembly.

    let res = oxygenhub::router(app.clone())

        .oneshot(Request::builder().uri("/static/backdrop/backdrop_bg.wasm").body(Body::empty()).unwrap())

# Backdrops: living backgrounds for OxygenHub

## 1. What a backdrop is

| Page | Scene | Shows |

|---|---|---|

| Dashboard | **Your sky** (§5) | Your repositories as clusters; their activity in the last 30 days as the marks around them |

| Sign in, register, device sign-in | **The mark** | The Oxygen mark's two rings with marks orbiting them; brand only, no data |

| A repository's Diffusion tab | **Ripples** | The upstream and its consumers as the Diffusion mark draws them: a pulse goes out on a bump, green or red as its run ends |

| Admin › Runners › Images | **The swarm** | Runners as nodes; chunks moving between them while an image is fetched, from the swarm tracker's live state |

{% extends "base.html" %}

{% block title %}Dashboard{% endblock %}

{% block content %}

<div class="head">

  <h1>Dashboard <small>signed in as {% if let Some(u) = shell.user %}{{ u }}{% endif %}</small></h1>

</div>

{% extends "base.html" %}

{% block title %}{% if let Some(o) = owner %}{{ o }}{% else %}Repositories{% endif %}{% endblock %}

{% block content %}

<div class="head">

  {% if let Some(o) = owner %}<h1>{{ o }} <small>{{ repos.len()|plural("repository", "repositories") }}</small></h1>

  {% else %}<h1>Repositories <small>{{ description }}</small></h1>{% endif %}

{% if repos.is_empty() %}

<p class="empty">No repositories yet. Create one with <code>oxygenhub admin repo create OWNER/NAME</code>, then <code>oxy push</code> into it.</p>

{% else %}

{% for r in repos %}

  <li>

    <div>