docs: preregister engineering pilots and evaluation rubric

[TheAmericanMaker]

Summary

• Preregister a real test-isolation bug pilot (Tests: the git-config guard misses config injected through GIT_CONFIG_COUNT #412) and a bounded capability-filter feature pilot for E11, with exact target revision, preserved behavior, allowed scope, and observable acceptance checks.
• Add an evaluation rubric covering correctness, evidence identity, independent review, actual human acceptance, interruption/recovery, negative controls, second-change continuity, effort, and overhead.
• Clarify that dependency eligibility does not override maintainer scheduling holds. E09 remains on hold; E01 ownership and all E11 prerequisites are unchanged.

Scope and evidence

Documentation only. Neither pilot has been implemented, no new feature assignment was created, and this PR does not authorize execution or provider spend.

Selection checks on pinned target ee091ac680eef4824ad378b4aa958829a21d89cd:

• Build and full suite: 948/948 passed.
• Library test control: 72/72 passed.
• Injected Git configuration reproduction: 71 passed, 1 named failure, process exit 1 as expected.
• Synthetic capability metadata is stored, but current core/public schema lacks the proposed capability filter. This is feature-absence evidence, not a regression claim.

The known-answer bug is explicitly not a diagnostic benchmark. Historical target and future engine revisions are distinct. The application test-data library is not a required synthesis-reference library.

Verification and publication safety

• Independent read-only review: APPROVE for the staged documentation and retained selection evidence.
• Incorporated the nonblocking suggestion to explicitly cover MCP empty-string and non-string filter inputs in the acceptance checklist; these behaviors were already specified in the reviewed contract.
• Build and full test suite passed; staged diff, relative links, and sensitive-content checks passed.
• Only three Markdown files. No raw machine logs, private paths/configuration, credentials, or session transcripts included.

Refs #409
Refs #398

No version bump, release, deployment, E09 implementation, or E01 contract change.