Fix the permission gate, which failed open on every single tool call

[QuintinBotes]

Found by running the app, not the suite. A Thread's timeline held 106 identical lines:

PreToolUse:Bash failed (exit 1) — Tervin hook: Tervin did not answer within 5s.

The bug

HookHandler::decide was sync; PermissionArbiter::decide is async. ArbiterHandler bridged them with Handle::block_on, which serve_one calls from inside tokio::spawn. Blocking a runtime worker from within the runtime panics: the task died, the socket closed with no reply, the client waited out its full 5s and exited 1.

Exit 1 is non-blocking. So the gate failed open on every tool call, silently, while the UI stated it was gating the session. That is precisely the class of dishonesty this project exists to avoid, so it is the most serious bug found so far.

The trait is async now, so nothing bridges. The runtime: Handle field is deleted rather than moved to a blocking pool, because the bridge was the bug.

Why the suite missed it

ArbiterHandler is the only handler Tervin ever constructs, and it was the only one with no test. Every gate test, including the live one against the real CLI, used a trivial handler that returned a decision directly and never called block_on. Same shape as the BlocksPanel failure docs/TESTING.md opens with: the code that ships was the code never exercised.

Two tests now drive the real handler through the real socket and the real client, asserting on exit codes rather than decisions, because exit 1 is the signature of "no answer" and a decision assertion passes for a timeout. One covers deny and defer; one covers 6 concurrent calls, since serve_one spawns per connection specifically so a slow decision cannot delay the next, and nothing asserted that.

Verified the guard fires: reintroducing block_on fails the new test with the identical message from the screenshot.

Four things that made the app unreadable

All found the same way, by using it:

• Repeated timeline events collapse to one row with ×N. The information in the hundredth repeat is the count. Only consecutive identical events merge, so nothing is reordered and an interleaved event breaks the run, which is asserted.
• A Block's command wrapped one character per line in a narrow pane: pre-wrap plus break-word on a flex child that can shrink to nothing. Now one truncated line, full text in the tooltip and the expanded body.
• The Plan tab put a Thread title mid-sentence. Titles come from the first prompt, so it read as gibberish. The Thread is already named in the header.
• Titles were 80 chars cut mid-word. Now 48, cut at a word boundary, whitespace collapsed so a pasted prompt cannot put newlines in a title.

682 rust, 321 vitest, clippy clean, fmt clean, tsc clean.

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