P2: instance_name does not reach the page chrome; the tab title and brand label stay Vole

instance_name reaches the heading but not the page chrome. On an instance configured with instance_name = "Rodent Software", the landing page has <h1>Rodent Software</h1> and the browser tab still reads:

<title>Repositories · Vole</title>

Why it matters

A forge that is deployed for an organisation is renamed on purpose: the name is the product the organisation runs, and instance_name exists precisely for that (docs/configuration.md, the status page reports it). Every page still calls itself “Vole” in the one place a reader always looks — the tab — and in the brand link’s accessible name, which is what a screen reader announces.

Where

• server/web/templates/chrome.html:14 — <title>{{.Title}} · Vole</title>
• server/web/templates/chrome.html:33 — aria-label="Vole home" on the brand link
• server/web/status.go:297 and home.go:55 already use the configured name, so the plumbing exists; the template just does not reach for it.

server/web/templates/status.html:214 also says “restart Vole” in prose. That one is a judgement call: product name or instance name.

Scope

• Use the instance name in the document title, with the configured default (Vole) when instance_name is empty, and keep the {{.Title}} order that pages already rely on.
• Use it in the brand link’s accessible name; avoid rendering a dangling separator when the name is empty.
• Decide about prose mentions such as the status page’s instruction, and about any other place that hardcodes the product name.
• Check the same through grep -rn 'Vole' server/web/templates/ so the list is complete rather than one instance deep.

Acceptance criteria

• With instance_name = "Rodent Software", the tab reads Repositories · Rodent Software and the brand link announces “Rodent Software home”.
• With instance_name unset, nothing renders a bare separator or an empty label.
• The rendered <h1>, tab title, and accessible name agree on every page that has a document title.