docs: fix dead README pointer in CLAUDE.md must-read list (#73)

Follow-up to #72, same class of defect.

`CLAUDE.md`'s must-read list pointed at **`README_JTV.md`, which does
not exist**. The main README is `README.adoc`.

## Full sweep of that list

I swept every backtick-quoted path in the must-read list rather than
fixing just the one I tripped over:

| Entry | Status |
|---|---|
| `README_JTV.md` | **DEAD** → fixed to `README.adoc` |
| `STATUS.adoc` | OK (fixed in #72) |
| `docs/GRAMMAR_EVOLUTION.md` | OK |
| `docs/QUANTUM_VISION.md` | OK |
| `Justfile` | OK |
| `Cargo.lock` | OK |
| `target/` | build directory — expected absent until a build runs, not
a defect |

Relative markdown links in `README.adoc`, `LICENSING.md` and
`CONTRIBUTING.md` were also swept: no dead links.

One line changed. No source, proof, workflow, or manifest files touched.

Context: `dev-notes/jtv-sitrep-2026-07-27.md`.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

Author: hyperpolymath

CLAUDE.md

@@ -75,7 +75,7 @@ Specification in `docs/`:
 
 Must-read files for context:
 
-- `README_JTV.md` - Main project README
+- `README.adoc` - Main project README
 - `STATUS.adoc` - Current implementation status (canonical)
 - `docs/GRAMMAR_EVOLUTION.md` - v1 vs v2 separation rationale
 - `docs/QUANTUM_VISION.md` - Quantum computing abstraction