An issue with hundreds of comments shows its newest 50 and one link for the earlier ones: issue #334's page under 250 KB #6124

Measured on 2026-10-26: /trevato/forge/issues/334 is 1.3 MB because it renders all ~480 comments. A phone loads every one of them to read the last.

Done when:

• [ ] An issue or pull thread renders the opening post and its newest 50 timeline items. Above them is a link, Show N earlier, to ?all=1, which renders everything. It works without JavaScript.
• [ ] A comment's own anchor (#c-…) still lands: when it is in the hidden part, the link goes to ?all=1#c-…, and a test covers that.
• [ ] A test seeds 300 comments and asserts that the default page has 50 items, the link names 250, the body is under 250 KB, and ?all=1 has all 300.

Files: src/web/studio/tell.ts (the thread), test/thread-window.test.ts. Risk: the live region that appends new comments must keep appending at the bottom.