Single navigation entry point. Existing docs were scattered
across five branches with no clear reading order — this is
the fix. Includes:
- 3-doc fast path for anyone joining
- topic-grouped table (algorithm / experiments / design
discussions / evaluation / environment / archive)
- role-based reading paths (new SWE, paper reviewer,
reproducing student, control-plane reader)
Index also references the four docs added later on this
branch (AUDIT_AND_ROADMAP, BLOCK_LEVEL_EVICTION_DESIGN,
D_TO_P_SYNC_CONTRACT, EVALUATION_PROTOCOL) so reviewers
can see the planned layout up front.