ci: remove hardcoded version from _version.py via post_generate.py

.genignore

@@ -1 +1,2 @@
 pyproject.toml
+src/airbyte_api/_version.py

src/airbyte_api/_version.py

@@ -1,15 +1,22 @@
-"""Code generated by Speakeasy (https://speakeasy.com). DO NOT EDIT."""
+"""Runtime version and Speakeasy generation metadata.
+
+__version__ is resolved from installed package metadata (set at build time
+by uv-dynamic-versioning from the git tag).  The remaining constants are
+Speakeasy generation metadata updated on each regeneration.
+"""
 
 import importlib.metadata
 
 __title__: str = "airbyte-api"
-__version__: str = "1.0.0"
-__openapi_doc_version__: str = "1.0.0"
-__gen_version__: str = "2.911.0"
-__user_agent__: str = "speakeasy-sdk/python 1.0.0 2.911.0 1.0.0 airbyte-api"
 
 try:
-    if __package__ is not None:
-        __version__ = importlib.metadata.version(__package__)
+    __version__: str = importlib.metadata.version(__title__)
 except importlib.metadata.PackageNotFoundError:
-    pass
+    __version__ = "0.0.0"
+
+__openapi_doc_version__: str = "1.0.0"
+__gen_version__: str = "2.911.0"
+__user_agent__: str = (
+    f"speakeasy-sdk/python {__version__} {__gen_version__}"
+    f" {__openapi_doc_version__} {__title__}"
+)