restore, step 2: resume agents, retype command lines

- the pi extension reports its session file; the daemon keeps it in the
  pane option @agent_session, and snapshots carry it. restore runs
  `pi --session <file>` in the rebuilt pane, one agent every 0.5s, then
  reports which agents run and which were interrupted mid-turn.
- other panes: the command line running in them is typed at the new
  prompt but not run. exactly as typed with the zsh hook (dingger install
  zsh: preexec/precmd keep @dingger_cmd), else the foreground program's
  exact argv from the kernel (KERN_PROCARGS2), shell-quoted.
- "at a prompt" is the pane's own shell owning the terminal's foreground
  process group, not a name check: `sh -c ...` is a running program.
- an agent or command that exits keeps its place in snapshots for 60s, so
  a shutdown that stops programs before tmux still restores them.
- typing waits for each new prompt (text typed earlier echoes twice).

e2e step 16 covers resume with a session path containing a space, the
interrupted report, an agent that exits just before the server dies, a
quoted command retyped not run, and the hook's text; dropping the grace
period, judging prompts by name, running retyped commands, or not storing
the session reference each fail it. the test's fake pi is guarded so a
real pi never starts.

1 files changed, 5 insertions, 2 deletions

diff --git a/crates/dinggerd/src/tmux.rs b/crates/dinggerd/src/tmux.rs
index 4e2b370..b1a2d60 100644
--- a/crates/dinggerd/src/tmux.rs
+++ b/crates/dinggerd/src/tmux.rs
@@ -27,6 +27,7 @@ pub struct Pane {
     pub written_since: String,
     pub written_hook: String,
     pub written_name: String,
+    pub written_session: String,
 }
 
 impl Pane {
@@ -110,14 +111,15 @@ pub fn list_panes() -> Result<Vec<Pane>, String> {
         "#{window_panes}\t",
         "#{pane_index}\t",
         "#{pane_current_path}\t",
-        "#{@agent_name}",
+        "#{@agent_name}\t",
+        "#{@agent_session}",
     );
     let out = run_tmux(&["list-panes", "-a", "-F", format])?;
     let mut panes = Vec::new();
     let mut process_tree = None;
     for line in out.lines() {
         let fields: Vec<&str> = line.split('\t').collect();
-        if fields.len() < 18 {
+        if fields.len() < 19 {
             continue;
         }
         let current_command = fields[1];
@@ -154,6 +156,7 @@ pub fn list_panes() -> Result<Vec<Pane>, String> {
             written_since: fields[11].to_string(),
             written_hook: fields[12].to_string(),
             written_name: fields[17].to_string(),
+            written_session: fields[18].to_string(),
         });
     }
     Ok(panes)