restore Claude Code agents in their own sessions

`dingger install claude` adds a SessionStart hook to Claude's settings
(every other key and hook kept, in order; the original backed up; written
through a symlink; installing again changes nothing). The hook is
`dingger hook claude`: it reports the session's transcript for its tmux
pane, prints nothing (Claude adds SessionStart output to the conversation)
and always exits 0. Claude's state still comes from its screen.

restore types `claude --resume <id>` in the directory the session ran in
(elsewhere, Claude moves the conversation there). it resumes an agent only
when its session file exists: a Claude session that never got a message
has no transcript, and `--resume` fails ("No conversation found"). the
snapshot now keeps an agent's command line too, so such a pane gets it
retyped instead of nothing.

- the hook receiver takes a report without a state: only the session.
- a report that arrives after the watcher listed the panes is not dropped
  as "agent gone": Claude reports once, as it starts.
- serde_json preserve_order (indexmap is already a dependency, via toml).

e2e step 18: install against a settings file like a real one, a fake
claude running the exact installed hook command, resume by id, retype
without a transcript, the resumed agent reporting again. a server that
restore starts now gets the test's plain shells: it got the user's login
shell, whose profile put the real claude first, which started (stuck at
its trust dialog) during development. every test restore now checks that
no real pi or claude runs in a test pane.

1 files changed, 12 insertions, 3 deletions

diff --git a/README.md b/README.md
index 475f659..9a67c2d 100644
--- a/README.md
+++ b/README.md
@@ -64,9 +64,12 @@ than a poll is still a completion.
   to preview, `--list` for saved snapshots, `--session` for some). Sessions
   that exist are left alone, except a bare one of the same name (what a
   terminal creates on startup), which is replaced with its clients moved
-  over. Agents are resumed in their own sessions (pi: `pi --session
-  <file>`, reported by the pi extension); agents that were mid-turn are
-  listed. Other panes get the command line that was running typed at the
+  over. Agents are resumed in their own sessions: pi with `pi --session
+  <file>` (reported by the pi extension), Claude Code with `claude --resume
+  <id>` (reported by its SessionStart hook, `dingger install claude`), in
+  the directory they ran in. A session that never got a message has nothing
+  to resume, so its command line is typed instead. Agents that were
+  mid-turn are listed. Other panes get the command line that was running typed at the
   prompt, not run: exactly as typed with the zsh hook (`dingger install
   zsh`, then source the file it names from your `.zshrc`), otherwise the
   program's arguments. An agent or program that exits within a minute
@@ -89,6 +92,10 @@ than a poll is still a completion.
 1. **Agent hooks** (authoritative): `dingger install pi` installs a pi
    extension that reports working/blocked/idle over
    `~/.local/state/dingger/agent.sock`. Restart running pi agents to load it.
+   `dingger install claude` adds a SessionStart hook to
+   `~/.claude/settings.json` (keeping everything else; the original is
+   backed up to `settings.json.bak-dingger`) that reports only Claude's
+   session, for restore; its state comes from screen matching.
 2. **Screen matching** (fallback): `capture-pane` text through herdr's
    manifests, for agents without hooks.
 
@@ -102,6 +109,8 @@ dingger watch                 # the daemon (run by launchd, see below)
 dingger status                # agents in priority order
 dingger focus [--pane ID]     # jump to an agent (default: the top waiter)
 dingger install pi            # install the pi state-reporting extension
+dingger install claude        # report Claude Code sessions, for restore
+dingger install zsh           # record typed command lines, for restore
 dingger manifests update      # refresh manifests from herdr's catalog
 ```