feat: Stop archives a session, Sleep keeps it; SSH keys per type (#82); update Auto fix

- Stop (a tab's or pane's X, Close tab) now archives the session it held
  (DELETE /api/run/:id?archive=1); the new Sleep (moon left of the X, and in
  the tab, pane and session right-click menus) stops the pane but keeps the
  session listed to resume later. Shared endRuns in client/src/lib/stopSession.ts.
- Git identity (#82): an account keeps an ED25519 AND an RSA key (AWS
  CodeCommit takes only RSA), every ssh git offers both, and a member's
  ~/.gitconfig gets core.sshCommand so a git typed in a terminal uses them.
- Update dialog: Auto fix starts a Claude Code session on the install
  folder with the failed update's error.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/SERVER-MODE.md

@@ -562,7 +562,7 @@ What runs as the member, and how:
   - In a member's folder, git and `gh` run as `sudo -n -u ah-<name> git …`, so git's own ownership check passes and every file stays the member's.
   - The editor and `.gitignore` saves go through `/opt/agenthub/libexec/write-as`.
   - A file uploaded in the Files tab (`POST /api/lanes/:id/git/upload`) is written the same way, AS the member through `write-as` (content on stdin), and only as a NEW file in an existing folder of the workspace — never over an existing name, never into `.git`, never a home dot folder, at most 25 MB. With **Download** on a file (`GET /api/lanes/:id/git/download`, read like any member file below, up to 512 MB) this is how a member with no SSH or `scp` to the host moves files in and out of their own folder; both work in a folder that is not a git repo.
-  - AgentHub's stored git logins are never handed to a member's git, and a password typed in the git bar goes into the member's OWN store (below) for that one call — through `write-as`'s stdin, never sudo's argv or env — and out again unless "remember" was ticked; a store that cannot be read is never rewritten (`409 ESTOREUNREADABLE`). The member keeps their OWN identity in Settings → Git → **Your git identity** (`/api/me/git`): a commit author (`user.name`/`user.email` in their `~/.gitconfig` — commits fail without one; a new member has none), an SSH key AgentHub makes for them and HTTPS logins, both under `~/.config/agenthub/` in their home, written as them by `write-as` (0600). Add workspace → **Clone** (`POST /api/lanes/clone`) clones as them with it and writes it into the clone's own config (`core.sshCommand` / `credential.helper=store --file=…`), so the git bar and their agents' pushes in that repo use it too. A login typed in the Clone dialog goes to their store through `write-as`'s stdin, never sudo's argv or env, and is removed again after the clone unless "remember" was ticked.
+  - AgentHub's stored git logins are never handed to a member's git, and a password typed in the git bar goes into the member's OWN store (below) for that one call — through `write-as`'s stdin, never sudo's argv or env — and out again unless "remember" was ticked; a store that cannot be read is never rewritten (`409 ESTOREUNREADABLE`). The member keeps their OWN identity in Settings → Git → **Your git identity** (`/api/me/git`): a commit author (`user.name`/`user.email` in their `~/.gitconfig` — commits fail without one; a new member has none), SSH keys AgentHub makes for them (an ED25519 and/or an RSA one — AWS CodeCommit takes only RSA) and HTTPS logins, both under `~/.config/agenthub/` in their home, written as them by `write-as` (0600). Add workspace → **Clone** (`POST /api/lanes/clone`) clones as them with it and writes it into the clone's own config (`core.sshCommand` / `credential.helper=store --file=…`), so the git bar and their agents' pushes in that repo use it too. A plain `git` they type themselves in a pane reads none of that, so making the key also sets `core.sshCommand` in their `~/.gitconfig` (the key first, then `~/.ssh/id_*`; a switch under the key, issue #82) — unless they already set their own, which is left alone. A login typed in the Clone dialog goes to their store through `write-as`'s stdin, never sudo's argv or env, and is removed again after the clone unless "remember" was ticked.
 - **Files a pane reads.** These are written into `~/.agenthub/handoff/` AS the member (`write-as`). The dashboard never writes, changes or deletes anything in a member's home itself: the member could have swapped the name for a link. The files are:
   - the workspace prompt and its context files;
   - the AI Proxy settings: no key, only that pane's own token for the gateway;