fix(imaging): keep avatars rendering, cacheable and reliably timed

Effect renders need a little over 4s, which the 4s primary timeout cut off,
so every avatar with the default effect fell through to an unreachable
public fallback and rendered as a placeholder. Raise the primary budget
above the observed render cost and shorten the fallback budget.

Also stop the proxy from stamping no-store over the avatar and media
responses, so browsers keep the long-lived Cache-Control the route already
sends, and recreate the imaging cache directories with the container user
on every deploy, since root ownership made those cache writes fail
silently.

src/lib/imager-upstream.ts

@@ -14,8 +14,13 @@ export const FIGURE_MAX_PARTS = 24;
 
 const HABBO_PUBLIC_UPSTREAM = "https://www.habbo.com/habbo-imaging/avatarimage";
 
-const PRIMARY_TIMEOUT_MS = 4_000;
-const FALLBACK_TIMEOUT_MS = 4_000;
+// Effect renders (the client asks for effect=14 by default) are encoded as
+// APNG animations and consistently need a little over 4s, so the primary
+// budget has to stay well above that or every effected avatar times out. The
+// public Habbo renderer is a best-effort safety net only: it is slow to fail,
+// so it gets a short budget and the disk cache absorbs the difference.
+export const PRIMARY_TIMEOUT_MS = 8_000;
+export const FALLBACK_TIMEOUT_MS = 2_000;
 
 export type ImagerSource =
 	| "primary"