Fix multiple loading of nodes

[wollew]

The current code replaces instances of Node with new instances every time PyVLX.load_nodes() is called, even when the actual the device in the gateway didn't change. This leaves dangling callbacks and potentially leaks memory. This PR changes the code that gateway devices which are considered "physically the same device" (=either identical serial number or no serial number available but identical node id) do not generate new node instances.
Multiple calls to PyVLX.load_nodes() will be necessary in order to fulfill HA's "dynamic devices" quality scale rule.

[github-actions]

Coverage report

Click to see where and how coverage changed

File	Statements	Missing	Coverage	Coverage (new stmts)	Lines missing
src/pyvlx
node.py					40, 57, 73, 84
nodes.py					63-67, 109, 116, 129, 132, 138, 150
Project Total

This report was generated by python-coverage-comment-action

[Copilot]

Pull request overview

This PR prevents repeated PyVLX.load_nodes() calls from unnecessarily replacing Node instances (which can leave dangling callbacks), by introducing node identity matching and explicit disposal/unregistration for nodes that are replaced or removed.

Changes:

• Add Node.dispose() and Node.represents_same_node() to support safe lifecycle management and identity matching.
• Change Nodes._load_all_nodes() / _load_node() to merge snapshots by physical identity (serial, or node_id fallback when both serials are missing) instead of always recreating nodes.
• Expand unit tests to assert callback unregistration on clear/replace and identity-preserving reload behavior.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
src/pyvlx/node.py	Adds disposal and identity helper used to preserve node instances across reloads.
src/pyvlx/nodes.py	Disposes replaced/cleared nodes and merges loaded snapshots to keep existing instances when appropriate.
test/nodes_test.py	Adds tests for disposal behavior and for identity-preserving _load_all_nodes() / _load_node() behavior.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.