turn: spawn claude with cwd = /state

every claude invocation now runs with current_dir set to
/state — relative paths in tool calls (Read notes.md, Bash ls,
Write blob) land in the agent's durable bind-mounted dir
instead of the harness's systemd cwd. /state is RW + survives
destroy/recreate so this matches where the agent is told to
keep notes anyway. dev/test setups without the bind silently
fall back to the parent cwd.

hive-ag3nt/src/turn.rs

@@ -241,6 +241,16 @@ async fn run_claude(
         ));
     }
     let mut cmd = Command::new("claude");
+    // Spawn inside /state so any path claude resolves relatively (Read
+    // foo.md, Bash ls, Write notes.md) lands in the agent's durable
+    // dir instead of wherever the harness systemd unit started. /state
+    // is bind-mounted RW from the host so survives destroy/recreate.
+    // Fall back silently if the dir is missing (dev / test setups
+    // running without the bind mount) — Command picks up the parent's
+    // cwd in that case.
+    if std::path::Path::new("/state").is_dir() {
+        cmd.current_dir("/state");
+    }
     cmd.arg("--print")
         .arg("--verbose")
         .arg("--output-format")