restore(lang): full lang tree from ff3ef452 (306 files) — compiler, vm, shared, runner, c-abi, etc.\n\n- Restores lang/ directory (files≈306, dirs≈64) as per historical branch with selfhost sources\n- Keeps our recent parser index changes in compiler/* (merged clean by checkout)\n- Unblocks selfhost development and documentation references

lang/src/shared/json/json_cursor.hako

@@ -0,0 +1,44 @@
+// json_cursor.hako — JsonCursorBox (thin scan facade)
+// Responsibility: provide a minimal, escape-aware scanning facade used by JsonFragBox
+// Delegates to StringOps, StringScanBox and JsonScanBox.
+
+using "lang/src/shared/common/string_ops.hako" as StringOps
+using "lang/src/shared/json/core/string_scan.hako" as StringScanBox
+using "lang/src/shared/json/core/json_scan.hako" as JsonScanBox
+
+static box JsonCursorBox {
+  index_of_from(hay, needle, pos) {
+    return StringOps.index_of_from(hay, needle, pos)
+  }
+  // Alias: find_from (compat)
+  find_from(hay, needle, pos) { return me.index_of_from(hay, needle, pos) }
+  scan_string_end(text, quote_pos) { return StringScanBox.scan_string_end(text, quote_pos) }
+  seek_array_end(text, lbracket_pos) { return JsonScanBox.seek_array_end(text, lbracket_pos) }
+  seek_obj_end(text, start) { return JsonScanBox.seek_obj_end(text, start) }
+  find_key_dual(text, plain, escaped, pos) { return JsonScanBox.find_key_dual(text, plain, escaped, pos) }
+  // Extract a sequence of optional sign + digits starting at start_pos
+  digits_from(text, start_pos) {
+    if text == null { return "" }
+    local i = start_pos
+    local n = text.size()
+    local out = ""
+    if i < n {
+      local ch = text.substring(i, i+1)
+      if ch == "-" {
+        out = out + ch
+        i = i + 1
+      }
+    }
+    loop(i < n) {
+      local ch = text.substring(i, i+1)
+      if ch == "" { break }
+      if ch >= "0" && ch <= "9" {
+        out = out + ch
+        i = i + 1
+      } else { break }
+    }
+    return out
+  }
+}
+
+static box JsonCursorMain { main(args){ return 0 } }