fix: SSH executor uses source ~/.profile for remote PATH

SSH non-interactive sessions don't load .profile, causing 'claude: command not found'.
Prepend 'source ~/.profile 2>/dev/null;' to ensure user PATH is available.

Verified: end-to-end test passed (arm0 → WSL2 Claude Code, 77s execution).

src/execution/mod.rs

@@ -130,7 +130,7 @@ impl SshExecutor {
                 cmd.arg("-i").arg(key);
             }
             cmd.arg(format!("{}@{}", host.ssh_user, host.hostname))
-                .arg(command);
+                .arg(format!("source ~/.profile 2>/dev/null; {command}"));
             cmd
         };