The terminal's run screen says a word to a running crew run with `s`, as the run page's steer box and MCP `steer` do #7288

For: the owner watching a crew run go the wrong way in the terminal. Steering means one sentence redirects it without a browser.

steerRepoRun is reached from the run page's steer box and MCP steer (src/http/mcp/tools/steer.ts). The terminal's run screens (src/tui/screens/runs.ts, runlist.ts) cannot steer.

Done:

• [ ] On a running agent run, s opens a one-line composer; enter sends it through steerRepoRun and the screen shows the outcome (sent or commented) in MCP's words.
• [ ] Empty text is refused in place; a finished run is not offered s.
• [ ] Only a writer who is a person is offered s.
• [ ] A new test/tui-steer.test.ts: steer a running run and the word reaches it, empty text refused, an agent session has no s.

Files: the run screen under src/tui/screens/, one test. Risk: low.