fix(tui): honor client copy shortcut over ssh

- accept forwarded Cmd+C for selection copy in SSH sessions even when Hermes runs on Linux
- keep local Linux Alt+C from acting as copy and update TUI hotkey hints for remote shells

ui-tui/src/__tests__/platform.test.ts

@@ -31,6 +31,28 @@ describe('platform action modifier', () => {
   })
 })
 
+describe('isCopyShortcut', () => {
+  it('keeps Ctrl+C as the local non-macOS copy chord', async () => {
+    const { isCopyShortcut } = await importPlatform('linux')
+
+    expect(isCopyShortcut({ ctrl: true, meta: false, super: false }, 'c', {})).toBe(true)
+  })
+
+  it('accepts client Cmd+C over SSH even when running on Linux', async () => {
+    const { isCopyShortcut } = await importPlatform('linux')
+    const env = { SSH_CONNECTION: '1 2 3 4' } as NodeJS.ProcessEnv
+
+    expect(isCopyShortcut({ ctrl: false, meta: false, super: true }, 'c', env)).toBe(true)
+    expect(isCopyShortcut({ ctrl: false, meta: true, super: false }, 'c', env)).toBe(true)
+  })
+
+  it('does not treat local Linux Alt+C as copy', async () => {
+    const { isCopyShortcut } = await importPlatform('linux')
+
+    expect(isCopyShortcut({ ctrl: false, meta: true, super: false }, 'c', {})).toBe(false)
+  })
+})
+
 describe('isVoiceToggleKey', () => {
   it('matches raw Ctrl+B on macOS (doc-default across platforms)', async () => {
     const { isVoiceToggleKey } = await importPlatform('darwin')

ui-tui/src/app/useInputHandlers.ts

@@ -8,7 +8,7 @@ import type {
   SudoRespondResponse,
   VoiceRecordResponse
 } from '../gatewayTypes.js'
-import { isAction, isMac, isVoiceToggleKey } from '../lib/platform.js'
+import { isAction, isCopyShortcut, isMac, isVoiceToggleKey } from '../lib/platform.js'
 
 import { getInputSelection } from './inputSelectionStore.js'
 import type { InputHandlerContext, InputHandlerResult } from './interfaces.js'
@@ -315,7 +315,7 @@ export function useInputHandlers(ctx: InputHandlerContext): InputHandlerResult {
       }
     }
 
-    if (isAction(key, ch, 'c')) {
+    if (isCopyShortcut(key, ch)) {
       if (terminal.hasSelection) {
         return copySelection()
       }

ui-tui/src/content/hotkeys.ts

@@ -1,15 +1,21 @@
 import { isMac } from '../lib/platform.js'
 
+const isRemoteShell = Boolean(process.env.SSH_CONNECTION || process.env.SSH_CLIENT || process.env.SSH_TTY)
 const action = isMac ? 'Cmd' : 'Ctrl'
 const paste = isMac ? 'Cmd' : 'Alt'
 
+const copyHotkeys: [string, string][] = isMac
+  ? [
+      ['Cmd+C', 'copy selection'],
+      ['Ctrl+C', 'interrupt / clear draft / exit']
+    ]
+  : [
+      ...(isRemoteShell ? ([['Cmd+C', 'copy selection when forwarded by the terminal']] as [string, string][]) : []),
+      ['Ctrl+C', 'copy selection / interrupt / clear draft / exit']
+    ]
+
 export const HOTKEYS: [string, string][] = [
-  ...(isMac
-    ? ([
-        ['Cmd+C', 'copy selection'],
-        ['Ctrl+C', 'interrupt / clear draft / exit']
-      ] as [string, string][])
-    : ([['Ctrl+C', 'copy selection / interrupt / clear draft / exit']] as [string, string][])),
+  ...copyHotkeys,
   [action + '+D', 'exit'],
   [action + '+G', 'open $EDITOR for prompt'],
   [action + '+L', 'new session (clear)'],

ui-tui/src/lib/platform.ts

@@ -5,8 +5,8 @@
  * as `key.meta`. Some macOS terminals also translate Cmd+Left/Right/Backspace
  * into readline-style Ctrl+A/Ctrl+E/Ctrl+U before the app sees them.
  * On other platforms the action modifier is Ctrl.
- * Ctrl+C is ALWAYS the interrupt key regardless of platform — it must never be
- * remapped to copy.
+ * Ctrl+C stays the interrupt key on macOS. On non-mac terminals it can also
+ * copy an active TUI selection, matching common terminal selection behavior.
  */
 
 export const isMac = process.platform === 'darwin'
@@ -34,6 +34,16 @@ export const isMacActionFallback = (
 export const isAction = (key: { ctrl: boolean; meta: boolean; super?: boolean }, ch: string, target: string): boolean =>
   isActionMod(key) && ch.toLowerCase() === target
 
+const isRemoteShell = (env: NodeJS.ProcessEnv = process.env): boolean =>
+  Boolean(env.SSH_CONNECTION || env.SSH_CLIENT || env.SSH_TTY)
+
+export const isCopyShortcut = (
+  key: { ctrl: boolean; meta: boolean; super?: boolean },
+  ch: string,
+  env: NodeJS.ProcessEnv = process.env
+): boolean =>
+  isAction(key, ch, 'c') || (isRemoteShell(env) && (key.meta || key.super === true) && ch.toLowerCase() === 'c')
+
 /**
  * Voice recording toggle key (Ctrl+B).
  *