feat: VSCode-style "Connect to remote host" SSH bootstrap (#107)

https://github.com/user-attachments/assets/0a2aa8eb-89a0-48fa-a73f-27041a816acb

## Summary

Implements the VSCode-style "Connect to remote host" flow for Harness's
existing multi-backend (Tier 1) system. The user picks an SSH host from
`~/.ssh/config` (or types a freeform `user@host`), Harness SSHes in,
installs `harness-server` if missing, starts it detached so it survives
disconnect, sets up an SSH local port forward, and hands the URL+token
to the existing `connections:add` flow.

This is the implementation of `plans/remote-main.md` §4 (and finishes §3
from the multi-backend Tier-1 work).

## Commits (recommended commit-by-commit review order)

1. `feat(ssh): parse ~/.ssh/config + add ssh-config listing IPC` —
`src/main/ssh-config.ts` + IPC handler + tests
2. `feat(ssh): node-ssh dependency + low-level bootstrap orchestrator` —
`src/main/ssh-bootstrap.ts` skeleton with progress events (no UI yet)
3. `feat(ssh): ssh-bootstrap slice + tunnel manager` — slice + tunnel
lifecycle code
4. `feat(ssh): BackendConnection.ssh field + boot-time reconnect` —
extends persistence + boot path
5. `feat(ssh): SSH tab in AddBackendModal` — UI piece
6. `feat(ssh): wire ssh:bootstrap into connections:add + progress log
UI` — final integration

## Manual smoke test

NOTE: This change required modifying the headless server, so testing
manually is kind of a long process. I had to manually build locally, SCP
the updated server over to the remote to replace the files already
installed from a previous version, and then connect remotely.

You might just have to trust me on this one that it works. We won't be
able to do a real full test until the new binary is in the GitHub
releases anyway

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: frenchie4111

package-lock.json

@@ -158,13 +158,15 @@
     "lucide-react": "^1.8.0",
     "monaco-editor": "^0.55.1",
     "node-pty": "^1.1.0",
+    "node-ssh": "^13.2.1",
     "playwright-core": "^1.59.1",
     "qrcode.react": "^4.2.0",
     "react": "^19.2.5",
     "react-dom": "^19.2.5",
     "react-markdown": "^10.1.0",
     "rehype-highlight": "^7.0.2",
     "remark-gfm": "^4.0.1",
+    "ssh-config": "^5.1.0",
     "ws": "^8.20.0"
   },
   "devDependencies": {

package.json

@@ -12,6 +12,7 @@ import { initialJsonClaude } from '../shared/state/json-claude'
 import { initialSnooze } from '../shared/state/snooze'
 import { initialAnnouncements } from '../shared/state/announcements'
 import { initialScratchpad } from '../shared/state/scratchpad'
+import { initialSshBootstrap } from '../shared/state/ssh-bootstrap'
 import {
   initialSettings,
   DEFAULT_LIGHT_THEME,
@@ -70,6 +71,7 @@ export function buildInitialAppState(
     snooze: config.snooze ? { byPath: { ...config.snooze } } : initialSnooze,
     announcements: initialAnnouncements,
     scratchpad: { byWorktreePath: flattenScratchpadNotes(config.scratchpadNotes) },
+    sshBootstrap: initialSshBootstrap,
     settings: {
       ...initialSettings,
       themeMode: