feat(lang): def REGISTRY from "file.lres" - a game fills an open registry from its own file

The entries are read and checked against the registry's record as a
registry ... from file is, errors at the resource file's line, and they
are defs of the module that wrote the line: the registry must be open to
it, and they take that module's place in the stable order. Reseed.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

selfhost/frontend/registry.ludic

@@ -75,9 +75,16 @@ function parse_registry() -> void {
   if from != null { res_read(v, from) }
 }
 # def REGISTRY key { field: value, ... }
+# def REGISTRY from "file.lres" - every entry of a resource file, as defs of this file's module
 function parse_def() -> void {
   pi += 1
   let reg = eat_id()
+  if is_id("from") and toks[pi + 1].kind == TK_STR {
+    let from = toks[pi + 1].text
+    pi += 2
+    res_read_into(reg, from, `def {reg} from`)
+    return
+  }
   let key = eat_id()
   skipnl()
   let rec = record()

selfhost/frontend/resource.ludic

@@ -16,9 +16,14 @@ function res_path(from: pointer, declaring: pointer) -> pointer {
   return join_path(dir_of(declaring), from)
 }
 function res_read(v: Node, from: pointer) -> void {
+  res_read_into(v.s, from, `registry {v.s}`)
+}
+# the entries of a resource file into registry `reg`, as defs of the reading file's module: a
+# registry's own file, or `def REG from "file.lres"` in a module that extends an open registry
+function res_read_into(reg: pointer, from: pointer, who: pointer) -> void {
   let path = res_path(from, g_parse_file)
   let src = read_file(path)
-  if src == null { perr(`registry {v.s}: cannot read the resource file {from}`) }
+  if src == null { perr(`{who}: cannot read the resource file {from}`) }
   let saved_toks = toks
   let saved_pi = pi
   let saved_file = g_parse_file
@@ -36,7 +41,7 @@ function res_read(v: Node, from: pointer) -> void {
     let key = eat_id()
     skipnl()
     let rec = record()
-    push(g_df_reg, v.s)
+    push(g_df_reg, reg)
     push(g_df_key, key)
     push(g_df_rec, rec)
   }