feat!: adopt Python 3.14 and 3.15 language features

- Require Python 3.15 for the server and Python 3.14 for the CLI.
- Match the server requirement to quart_common's Python 3.15 features.
- Replace future annotations with native deferred evaluation.
- Defer CLI command dependencies and QR imports on Python 3.15.
- Enable argparse suggestions for mistyped CLI commands.
- Remove the obsolete tomllib import fallback.
- Update my_helpers and quart_common submodule references.
- Lock test dependencies and exclude them from Docker installations.
- Add regression coverage for lazy imports and deferred annotations.
- Document runtime requirements and standalone CLI validation.
- Validate 276 tests on Python 3.15 and 18 CLI tests on Python 3.14.

BREAKING CHANGE: The server now requires Python 3.15+ and the standalone CLI requires Python 3.14+.

pyproject.toml

@@ -3,7 +3,7 @@ name = "nanoshare"
 version = "1.27.4"
 description = "Add your description here"
 readme = "README.md"
-requires-python = ">=3.14"
+requires-python = ">=3.15"
 dependencies = [
     "aiohttp>=3.13.3",
     "aiologger>=0.7.0",
@@ -20,6 +20,13 @@ dependencies = [
     "redis>=7.4.0",
 ]
 
+[dependency-groups]
+dev = [
+    "pytest>=8.0",
+    "pytest-asyncio>=0.24",
+    "watchdog>=6.0",
+]
+
 [tool.pytest.ini_options]
 testpaths = [
     "tests",