fix: address fourteenth round of Copilot PR review feedback

- Extract stable source_id from display label in reconciliation: parse
  'extension:foo v1.0' to 'foo' instead of passing the human-facing
  display string as source_id
- Fix bash lowercase to be POSIX-compatible: use tr instead of ${,,}
  which requires Bash 4+ and fails on macOS default Bash 3.2

Author: mnriem

scripts/bash/common.sh

@@ -442,7 +442,7 @@ except Exception:
     print('replace\t')
 " 2>/dev/null) && {
                                 IFS=$'\t' read -r strategy manifest_file <<< "$result"
-                                strategy="${strategy,,}"  # normalize to lowercase
+                                strategy=$(printf '%s' "$strategy" | tr '[:upper:]' '[:lower:]')
                             }
                         fi
                         # Try manifest file path first, then convention path

src/specify_cli/presets.py

@@ -675,9 +675,16 @@ def _reconcile_composed_commands(self, command_names: List[str]) -> None:
                 if not registered:
                     # Top layer is a non-preset source (extension, core, or
                     # project override). Register directly from the layer path.
+                    # Extract stable source_id from display label
+                    source = layers[0]["source"]
+                    if source.startswith("extension:"):
+                        # "extension:foo v1.0" → "foo"
+                        source_id = source.split(":", 1)[1].split(" ", 1)[0]
+                    else:
+                        source_id = source
                     self._register_command_from_path(
                         registrar, cmd_name, top_path,
-                        source_id=layers[0]["source"],
+                        source_id=source_id,
                     )
             else:
                 # Composed command — resolve from full stack
@@ -719,9 +726,14 @@ def _reconcile_composed_commands(self, command_names: List[str]) -> None:
                     shared_composed.mkdir(parents=True, exist_ok=True)
                     composed_file = shared_composed / f"{cmd_name}.md"
                     composed_file.write_text(composed, encoding="utf-8")
+                    source = layers[0]["source"]
+                    if source.startswith("extension:"):
+                        source_id = source.split(":", 1)[1].split(" ", 1)[0]
+                    else:
+                        source_id = source
                     self._register_command_from_path(
                         registrar, cmd_name, composed_file,
-                        source_id=layers[0]["source"],
+                        source_id=source_id,
                     )
 
     def _register_command_from_path(