Apply the ts-build-config (lib/types) convention to the new subagent packages

Master's #36 moved declaration output to lib/types (and types/exports/files
point there). The merge applied that to all pre-existing packages, but the
subagent backends introduced on this stack (subagent-inprocess, subagent-spawn,
subagent-fork) still used the old lib/ layout. Bring them onto the new
convention and add them to the single typecheck tsconfig.json references.

tsconfig.json

@@ -45,6 +45,9 @@
     { "path": "./packages/support/llm-replay" },
     { "path": "./packages/subagent/subagent" },
     { "path": "./packages/support/subagent-mock" },
-    { "path": "./packages/subagent/tool-subagent" }
+    { "path": "./packages/subagent/tool-subagent" },
+    { "path": "./packages/subagent/subagent-inprocess" },
+    { "path": "./packages/subagent/subagent-spawn" },
+    { "path": "./packages/subagent/subagent-fork" }
   ]
 }