docs: align top-level orientation docs with Phase V+H reality

The three highest-traffic orientation docs (00-START-HERE.md,
INDEX.md, READING_ORDER.md) were all v1.0.0-era — they described
OMC as a "circuit-evolution standalone executable" and referenced
files that don't exist (COMPLETION_SUMMARY.md, PROJECT_STATUS.txt).
After Phase V (self-hosting) and Phase H (self-healing compiler)
closed, new readers hitting these pages got an outdated picture
and broken file references.

00-START-HERE.md — full rewrite. Now opens with the current state
(2026-05-14), explicitly identifies the two arms of the project
(language work + circuit-evolution work), provides four tailored
reading paths (PL researchers, developers, circuit/GA, LLM-code
researchers), an honest "what's not in this repo" section, and a
table indexing every top-level doc.

INDEX.md and READING_ORDER.md — shortened to thin pointers that
redirect to 00-START-HERE.md and README.md. Preserved at their
URLs for anyone who linked to them before.

All file-path references in the three updated docs were verified.
The v1.0.0 era release-body file (RELEASE_BODY_v1.0.0.md) and
TIER_4_HONEST_REVISION.md were not touched — they are historical
artifacts accurate within their original scope.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: RandomCoder-lab