A test pins that an issue thread in the terminal never passes a terminal escape from a comment through #6978

src/tui/screens/thread.ts draws issue and pull timelines from markdown anyone with access can write, and no test opens it.

Done:

• [ ] A new test posts an issue body and a comment carrying ESC sequences (CSI colour, OSC 8 link, OSC 52 clipboard write, a bare BEL), then renders the thread screen. No raw ESC or BEL byte from the text reaches the output, and the visible text still reads.
• [ ] A viewer who cannot read the repository gets the terminal's own refusal and no title.
• [ ] The composer posts a comment as the signed-in person, and it shows in the timeline.

Files: test/tui-thread.test.ts

If the test finds the behaviour wrong, fix the module it names in the same pull and say so. If the check fails in a test this pull does not touch, name it in the pull rather than widening the change.

Before pushing: bun x tsc --noEmit and the new test.