hermes - 💡(How to fix) Fix fix(tui): Cmd+C over SSH kills the agent (splits PR #20421) [2 pull requests]

Problem

On macOS-over-SSH running hermes --tui, pressing Cmd+C (muscle memory for "copy selection") kills the agent because the TUI treats the forwarded modifier as Ctrl+C → interrupt. The user-visible symptom is: select text, hit Cmd+C to copy, agent exits.

PR #20421 tried to fix this plus several other things in one go. Review in #20421 requested a split — this issue tracks the minimum fix.

Prompt to Recreate

1. Local terminal: iTerm2 (or any terminal that forwards Cmd+C over SSH).
2. SSH to a host running Hermes.
3. hermes --tui.
4. Select text in the composer.
5. Press Cmd+C.

Expected: selection copies to the local clipboard (via OSC52 / tmux-buffer / kitty-protocol forwarding, whichever the transport supports). Actual: agent interrupts / exits.

Secondary bug on the way: on pre-kitty-keyboard iTerm2, pressing Option+C currently misclassifies as copy (because the classifier treats key.meta as Cmd), swallowing the ç character.

Scope (PR A)

• Keep ui-tui/src/lib/terminalSignals.ts + terminalShortcuts.ts + the useInputHandlers.ts / textInput.tsx wiring from #20421.
• Route both copy sites (input-buffer in textInput.tsx and terminal-selection in useInputHandlers.ts) through setClipboard() in @hermes/ink/termio/osc via a writeClipboardSmart helper in lib/clipboard.ts. Today useInputHandlers is smart but textInput is dumb.
• In classifyCopyChord, require key.super === true for Cmd-shape chords. This drops literal Cmd+C support on pre-kitty-keyboard terminals (acceptable; Ctrl+Shift+C is the documented fallback) but fixes the Option+C misclassification and keeps the actual SSH case working when the outer terminal speaks kitty-protocol.
• Ctrl+X queue-edit delete must stay independent of the shortcut classifier (Copilot comment 8).
• Fix the non-mac help text in content/hotkeys.ts (Ctrl+C = interrupt, Ctrl+Shift+C = copy).
• Delete terminalDoctor.ts, terminalProbe.ts, shellSignals.startupRiskHints, buildHelpHintHotkeys, updateTerminalProbe, plus their tests. These ship dead in #20421 and belong in the follow-up platform PR (tracked separately).
• Rebase onto origin/main (currently 224 commits behind).
• npm run lint --fix on touched files.

Non-scope

• No probe-time capability detection. That's PR B.
• No /doctor command. That's PR B.
• No capability-aware help hints in helpHint.tsx. That's PR B.
• No 21-profile registry exposed as a public API. Trim or scope internal.

Acceptance

• npm run lint clean on touched files.
• npm test green on terminalSignals, terminalShortcuts, clipboard, and the existing voice-shortcut / paste-path tests.
• Manual matrix (iTerm2 local / → tmux / → SSH / → SSH → tmux): Cmd+C with selection copies; Cmd+C without selection no-ops; Ctrl+C interrupts; Option+C inserts ç.

Context

• Replaces the bug-fix half of PR #20421 (platform half tracked separately).
• Split plan drafted in the repo workspace (PR20421_SPLIT_PLAN.md); contents mirrored to the #20421 review thread.
• OutThisLife's review on #20421: https://github.com/NousResearch/hermes-agent/pull/20421#pullrequestreview-4245048089 — full rationale.