docs(tasks): remove artificial contributor backlog

[codegeist-ai]

Tracking

• Repository Issue: No repository Issue; this is a maintainer-directed correction removing artificial tracking work.
• Canonical task or exception: T010_build-shared-github-contributor-foundation

Summary

Remove the three generated ready-work tasks and correct T010 so Issues and Roadmap items are created only for accepted concrete work. Preserve the completed contributor foundation, Roadmap structure, metadata, CI, and branch protection.

Verification

• task cli:check passed: 202 tests, 0 failures, 0 errors, 6 skipped; JVM packaging and license checks passed.
• git --no-pager diff --check passed.
• Confirmed no current documentation references the removed task names or Issue URLs.

Impact Checklist

• I did not include credentials, tokens, sensitive configuration, or private security details.
• I linked the applicable canonical task, or the owning repository permits no new task and I recorded the maintainer-approved reason.
• I assessed security implications and used private reporting where required.
• I assessed whether documentation, tests, or repository-specific checks need updates.
• I assessed whether a generated release branch needs an update.
• I assessed whether consumer repositories or pinned gitlinks need updates.
• Any applicable source -> generated release -> consumer gitlink sequence is documented or complete.
• I acknowledge that my intentional contribution is provided under 0BSD unless the target repository explicitly states another license.

No generated release or consumer gitlink update is required because all changed paths are source-only documentation.