feat: dependency fallbacks

[tandemdude]

Summary

Add ability to parse and inject union and optional parameters, including "meta annotations" to modify the injection behaviour for parameters

[codecov]

Codecov Report

Attention: Patch coverage is 88.76404% with 30 lines in your changes missing coverage. Please review.

Project coverage is 53.59%. Comparing base (0be9542) to head (c23234e).

✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
lightbulb/di/conditions.py	79.77%	18 Missing ⚠️
lightbulb/di/container.py	89.13%	5 Missing ⚠️
lightbulb/client.py	0.00%	4 Missing ⚠️
lightbulb/di/graph.py	98.97%	1 Missing ⚠️
lightbulb/di/registry.py	85.71%	1 Missing ⚠️
lightbulb/loaders.py	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #454      +/-   ##
==========================================
+ Coverage   51.10%   53.59%   +2.49%     
==========================================
  Files          35       37       +2     
  Lines        2671     2864     +193     
==========================================
+ Hits         1365     1535     +170     
- Misses       1306     1329      +23     

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