fix(portal): news timeline avatars fetch full-res image (render bypasses getAvatarUrl ?size=40)

Context

Operator-reported (2026-06-01): in most Portal news views, timeline avatars fetch the full-resolution image instead of a bounded thumbnail.

The Problem

Portal.view.content.Component already ships a getAvatarUrl(user) helper that returns ${repoUserUrl}${user}.png?size=40 (GitHub's ~1KB 40px image instead of the ~40KB original) — but the per-view timeline render paths bypass it, emitting the raw .png URL with no ?size=40:

• apps/portal/view/news/tickets/Component.mjs:267 (image: me.repoUserUrl + author + '.png'), :275 (<img src="${me.repoUserUrl}${author}.png">), :341, :350
• apps/portal/view/news/discussions/Component.mjs:203, :211, :349
• pulls view (same shared render pattern)

So every 40px timeline avatar downloads the full-res original.

The Fix

Route every avatar render through the base getAvatarUrl(user) (and the bot-fallback path the base already provides) so the ?size=40 bound is applied uniformly. No new config — the helper exists; the render sites just need to use it.

Acceptance Criteria

• AC1 — All Portal news timeline avatar <img>/vdom-image renders resolve their URL via getAvatarUrl (or the base avatar render helper), so the request carries ?size=40.
• AC2 — Bot/app actors still fall back to the no-network glyph (no regression to the existing bot handling).
• AC3 — A test asserts the rendered avatar URL is the bounded (?size=40) form for a normal user.

Out of Scope

• Changing the avatar source host or the bot-fallback list.

Related

• Epic #12204 (Portal news views).