feat: add L+ Jinja report materialization

[AlexanderLanin]

Summary

This draft PR adds the L+ proof of concept for model-complete Sphinx-Needs reports.

L+ keeps ordinary documentation reading parallel. During the read phase it records a report placeholder. After all worker environments have been merged, it renders the selected Jinja template against the resolved Needs model and materializes the resulting report in the existing document. The report outline is derived from Need links, and the template can use existing Sphinx-Needs directives such as needtable and needpie.

The previous manifest/generator experiment is intentionally not included. The report definition lives in src/needs_templates/mod_ver_report_tiny.need.

Evaluation conclusion

L+ is technically valid as a controlled solution for this report, but it is not a lightweight general-purpose extension. Sphinx does not provide a public API for adding model-complete sections and local table-of-contents entries after parallel Need collection has finished. L+ therefore needs a small compatibility layer around the cached doctree and the local ToC collector.

This makes L+ a reasonable prototype when automatic discovery from the Need graph is mandatory. It is not the simplest long-term option. If an explicit, reviewable component list is acceptable, the K approach from PR #730 is smaller, uses normal read-phase Sphinx sections and public APIs, and should be preferred.

The implementation should therefore be reviewed as an L+ experiment with a strict acceptance gate, not as proof that late materialization is a general replacement for ordinary Sphinx source processing.

Validation

• bazel test //src/extensions/score_sphinx_needs_templates:report_pipeline_tests
• bazel run //:docs

[github-actions]

License Check Results

🚀 The license check job ran with the Bazel command:

bazel run --lockfile_mode=error //src:license-check

Status: ⚠️ Needs Review

Click to expand output

[License Check Output]
Extracting Bazel installation...
Starting local Bazel server (8.6.0) and connecting to it...
INFO: Invocation ID: b9b0e40f-9487-4e07-822d-5f27b1575454
Computing main repo mapping: 
Loading: 
Loading: 0 packages loaded
Loading: 0 packages loaded
WARNING: Target pattern parsing failed.
ERROR: Skipping '//src:license-check': no such target '//src:license-check': target 'license-check' not declared in package 'src' defined by /home/runner/work/docs-as-code/docs-as-code/src/BUILD
ERROR: no such target '//src:license-check': target 'license-check' not declared in package 'src' defined by /home/runner/work/docs-as-code/docs-as-code/src/BUILD
INFO: Elapsed time: 5.227s
INFO: 0 processes.
ERROR: Build did NOT complete successfully
ERROR: Build failed. Not running target

[github-actions]

Documentation preview for this pull request is available at:
pr-769: https://eclipse-score.github.io/docs-as-code/pr-769/

[AlexanderLanin]

moving on to #763