Rewrite command parsing/serialization (#231)

* WIP

* Replace implicit polling tasks with explicit polling loop

* Get API unit tests passing

* Fix remaining unit tests

* Merge TX and RX schemas into a single object

* Match command responses by both command ID and the seq

* Increase test coverage

* Parse firmware structure

* Increase coverage

* Restrict `cancelling` to 3.11+

* Add unit test for `utils`

* Add unit tests for request retries

* Unit test request locking

Author: puddly

.pre-commit-config.yaml

@@ -19,7 +19,7 @@ repos:
           - --safe
 
   - repo: https://github.com/pycqa/flake8
-    rev: 6.0.0
+    rev: 6.1.0
     hooks:
       - id: flake8
         additional_dependencies: