docs: Improve discoverability of Jinja resources, filters, and schema references

[Copilot]

Documentation Improvements - All Complete ✅

All documentation improvements from the issue have been successfully completed. This PR enhances the discoverability and usability of Weaver's documentation for new and existing users.

Summary of Changes

✅ Enhanced Jinja Template Documentation

• Added "Learning Jinja Templates" section with external tutorial links
• Made resources more prominent in Weaver Forge README

✅ Documented Built-in Helper Functions

• Added comprehensive section on case converters (kebab_case, snake_case, etc.)
• Included usage examples and source code link to extensions directory

✅ Improved Schema Documentation Accessibility

• Added semconv schema to codegen.md quick links table
• Added weaver.yaml configuration to codegen.md quick links table
• Schema and configuration references are now easily discoverable in docs/codegen.md where users need them during code generation work

✅ Comprehensive Filter Documentation

• Added "Understanding Filters" section explaining:
  • Default behavior (no filter)
  • How filters transform data with raw JQ expression example
  • Common helper filters provided by Weaver
  • Filter options
  • The ctx variable and its interaction with filters

Files Modified

• docs/codegen.md - Added 130+ lines of documentation with relative links, quick reference table, and raw JQ expression examples
• README.md - Maintained concise, action-oriented structure per original design
• crates/weaver_forge/README.md - Enhanced with relative source link to extensions directory

Note: All markdown links use relative paths for better maintainability. Schema and configuration references are located in docs/codegen.md where users actively work with them, keeping the README focused on quick navigation to detailed documentation.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Documentation Improvements</issue_title>
<issue_description>Based on recent user feedback, several areas of the Weaver documentation could be improved to enhance clarity and ease of use. Below is a list of suggested improvements:

• Provide better documentation for Jinja templates. Many users may not have recent experience with Jinja, so linking to good external resources would be helpful. e.g.: 1, 2.
• Clarify where functions like kebab_case come from and document other built-in helper functions available in Weaver. Ideally, provide a direct link to the relevant source file.
• The semconv schema documentation should be more concise and prominently placed in the documentation hierarchy (both in JSON and Markdown formats).
• Improve accessibility of the Weaver YAML schema documentation by providing a more prominent and direct link.
• The filter parameter is confusing for first-time users. It would be useful to document:
  • The default behavior when no filter is applied.
  • Simple filtering examples.
  • Explanation of the ctx variable and how it interacts with filtering.</issue_description>

<agent_instructions>Check this issue for whether or not is up to date in accuracy, set your TODO list to include things that could be improved and issue a PR with those fixes.

Follow your other agent instructions.</agent_instructions>

Comments on the Issue (you are @copilot in this section)

Custom agent used: docs_agent
Expert technical writer for weaver

• Fixes Documentation Improvements #583

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[jsuereth]

@copilot Can you update all your markdown links to be relative?

[Copilot]

@copilot Can you update all your markdown links to be relative?

Updated all markdown links to relative paths in commit b3c6742. Changes include:

• docs/codegen.md: Converted all /crates/weaver_forge/... links to ../crates/weaver_forge/... and GitHub URLs to relative paths
• README.md: Changed /crates/weaver_forge/README.md to ./crates/weaver_forge/README.md
• crates/weaver_forge/README.md: Converted GitHub source links to relative ./src/extensions/... paths

Also removed DOCUMENTATION_IMPROVEMENTS_SUMMARY.md as requested.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 80.1%. Comparing base (b55473e) to head (db7fe27).
⚠️ Report is 5 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #1149     +/-   ##
=======================================
- Coverage   80.1%   80.1%   -0.1%     
=======================================
  Files        108     108             
  Lines       8440    8428     -12     
=======================================
- Hits        6763    6752     -11     
+ Misses      1677    1676      -1     

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