Astro 7, and stop a print-only instance calling a route it has switched off

The critical advisory in the dependency tree (GHSA-26w7-cxv4-gfx2, remote code
execution through AVIF image optimisation) has no fix inside Astro 5, so this
moves to Astro 7.3.2 with @astrojs/node 11 and current sharp. `npm audit` now
reports nothing. The only code the jump needed: `csp` graduated out of
`experimental`, and sharp's `Sharp` type is a named export now.

Also fixed, both found by testing with every module switched on rather than
only the print-only default:

- `src/pages/index.astro` passed `dict` to the studio island without ever
  defining it, so the studio page returned 500 on any instance with the AI
  module on. The print-only default redirects away from that page, which is
  why the earlier run never hit it.
- The print studio fetched `/api/delivery-targets` even with the delivery
  module off. The route answered 404 exactly as designed, but it left a red
  line in the console of every print-only instance, which reads like a fault.
  It now asks only when there is a module to ask, and hides the card otherwise.

Plus: the first-run box sizes itself to its content instead of miscounting
padding, and the README's counts are recounted rather than remembered.

Verified against a live instance on a fresh database, in both module sets:
sign-in, module gating, the German interface, an eight-up passport sheet and
its PDF. 124 tests, type check, build and secret scan all clean.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Nh4A79bbqT9dcd2inzYUdg

CHANGELOG.md

@@ -11,7 +11,8 @@ private repository as a personal tool.
   default is the print studio alone — no image model, no object store, no bot
   token, no account anywhere. See `src/lib/modules.ts`.
 - **English interface**, with German as a full second language. The English
-  sentence is the translation key; 1,038 strings.
+  sentence is the translation key; 1,067 entries, covering every translatable
+  string in the source.
 - **First-run setup.** No built-in accounts. The first boot creates one
   administrator from `ADMIN_USERNAME` / `ADMIN_PASSWORD`, or generates a password
   and prints it once to the log.
@@ -23,6 +24,7 @@ private repository as a personal tool.
 - English routes: `/print`, `/library`, `/queue`, `/shares`, `/help`, `/account`,
   `/tour`, `/password`.
 - AGPL-3.0, CI (build, tests, type check, secret scan), `CONTRIBUTING`, `SECURITY`.
+- Astro 7 and current `sharp`: `npm audit` reports no known vulnerability.
 
 **Carried over from the private tool**