docs/manuals/: Create user manual

[ryan-steel]

What

Summary

Create comprehensive user manual for inc_time module covering API usage, configuration, and examples.

Description

time module has working examples in examples/ directory and public API in include/, but no user-facing documentation explaining how to integrate and use the module. Following module_template pattern, need complete user manual covering API description, Bazel integration, and example usage.

Acceptance Criteria (DoD)

• API documentation covers public interfaces in include/
• Configuration section shows Bazel integration via MODULE.bazel
• All examples in examples/ documented with purpose and usage
• Build instructions for compiling and running examples
• Expected output documented for each example
• User manual integrated into docs/manuals/index.rst toctree
• bazel run //:docs generates HTML documentation
• Documentation follows SCORE docs conventions from docs-as-code/

How

• Document public API usage patterns and integration guide
• Show Bazel dependency setup and available build targets
• Document each example: what it demonstrates, how to build/run, expected output

Deliverables

• docs/manuals/user_manual.rst following module_template structure
• Sphinx/reStructuredText docs integrated with docs-as-code framework