docs: restructure security report as an audit field guide (where to look)

Reframed docs/security_report.md around the auditor's two questions — which
source-code regions to prioritize and which patterns to look for — and
de-emphasised the silent-fix meta-commentary. New centrepiece: the audit
priority map (fig9) plotting every subsystem by volume x severity density, with
three actionable groups (deep-audit crypto/EVM/consensus for critical bugs;
prioritise p2p/fork-choice/sync for both; sweep state-trie/RPC for DoS). Adds
attack-surface entry points, severity-driver ranking, the P1-P6 pattern smells,
a repeatable cross-implementation variant-hunting method, case studies, an audit
playbook, and transferable lessons for any blockchain / distributed-consensus
system. New fig9 priority map. README description updated.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: grandchildrice

README.md

@@ -218,7 +218,7 @@ docs/            BUILD_REPORT · IMPROVEMENT_LOG · silent_fix_detection · mode
 
 ## Documentation
 
-- [`docs/security_report.md`](docs/security_report.md) — 🔎 **Field guide for security researchers** — the bug-bounty severity model as premise, the severity-realization map (what pays → where to look), recurring anti-patterns, cross-client variant analysis, case studies, and a hunting playbook
+- [`docs/security_report.md`](docs/security_report.md) — 🔎 **Audit field guide** — where to look (the priority map: which source-code regions concentrate severe bugs), the attack surface, the recurring vulnerability patterns, cross-implementation variant hunting, and lessons transferable to any blockchain / consensus system
 - [`docs/analysis.md`](docs/analysis.md) — **what the data says** (silent-fix majority, availability-first vuln profile, cross-language diversity), read through the dataset-research literature
 - [`docs/limitations.md`](docs/limitations.md) — **honest inventory of coverage gaps & caveats** (read before relying on the data)
 - [`docs/severity_labeling.md`](docs/severity_labeling.md) — **methodology**: LLM severity estimation against the bug-bounty model (decompose → map → calibrate)