Extract attach-bsdl into core; add it to the wx GUI.

Second editing op into the wx frontend. Extract the logic (parse the .bsd,
apply it to the part, record bsdl_path) into core/app/edit.hpp::attach_bsdl
(Part*, path) -> {ok, error, entity, bound, unbound, ports_total}, failing
without mutation when the file can't be parsed.

The TUI `attach-bsdl` command now renders that result (output unchanged); the
wx GUI gains an Edit ▸ Attach BSDL… menu reusing PickPart() + a .bsd file
dialog. Prune the now-dead bsdl_model include from commands.cpp.

tests/test_edit.cpp: parse failure leaves the part untouched; null part. The
success path is covered by a batch run (entity + bound/total ports). 381 core
assertions green; tui + wx build clean.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/core/app/edit.hpp

@@ -22,6 +22,22 @@ struct SetConnectorTypeResult {
 // (ok=false, error set, no mutation) when the kind is invalid for the part.
 SetConnectorTypeResult set_connector_type(Part *part, const std::string &kind);
 
+// Outcome of attaching a BSDL model to a part. On success the part's pin specs
+// are filled from the model and its bsdl_path is recorded.
+struct AttachBsdlResult {
+    bool ok = false;
+    std::string error;     ///< set when the .bsd cannot be parsed
+    std::string entity;    ///< the BSDL entity name
+    int bound = 0;         ///< ports matched to a pin
+    int unbound = 0;       ///< ports with no matching pin
+    int ports_total = 0;   ///< ports declared in the model
+};
+
+// Parse the BSDL file at `path` and apply it to `part` (fills each pin's role
+// and direction; records bsdl_path). Fails (ok=false, error set, no mutation)
+// when the file cannot be parsed.
+AttachBsdlResult attach_bsdl(Part *part, const std::string &path);
+
 }  // namespace app
 
 #endif  // _APP_EDIT_HPP_