refactor: integrate compilation-owned identifier interning

source/strpool/strpool.hon

@@ -4,13 +4,11 @@ import "@std/hashmap"
 
 InternError :: enum { out_of_space }
 
+#! identifies a string only within its owning pool.
 StringId :: alias u32
 
 no_str :: maxval!(StringId)
 
-#! global pool owned by main.hon; initialize before scanning and release with deinit.
-strings StringPool := undefined
-
 #! retains its allocator and owns interned copies; release all storage with deinit.
 StringPool :: struct {
     ids hashmap.StringHashMap(StringId) # string → id