docs(readme): rewrite engineering showcase, JIT sealing protocol, and persona matrix

[nicolasvd]

PR Walkthrough — Rewrite README as Engineering Showcase and Pre-Public Release Review

Closes #20

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📌 Context & Objectives

Addresses Finding R-01 from the initial 360° Architecture Audit by transforming the root README.md into an exhaustive, high-visibility engineering showcase in English. It establishes the repository as a reference implementation for deterministic multi-agent software engineering, documenting the sequential persona state machine, the 2 human-in-the-loop blocking gates, the Just-In-Time (JIT) sealing workflow, the isolated Epic branching protocol, and the comprehensive playbooks registry.

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🚀 Key Changes Delivered

1. Clean SVG Visual Banner (banner.svg):

   • Modern, high-resolution vector banner (1200×420) modeled directly after the SaaS blueprint pattern of sales-agents-agy.
   • Incorporates ambient blue/emerald glows, light blueprint grid, top status pills (Antigravity 2.0 Native, Jetpack Compose & Roborazzi, Zero Rogue Commits), and 4 feature cards detailing PoLP, 2 blocking gates, JIT sealing, and the Quality Airbag.

2. Exhaustive Engineering Showcase (README.md):

   • Executive Overview & Value Proposition: Outlines the failure modes of unconstrained AI agents (hallucinations, rogue commits, premature coding) and the deterministic micro-kernel solution.
   • Sequential Persona State Machine: Preserves the official 3-phase lifecycle (Inception → Construction/Delivery & Testing via Quality Airbag → Release) with a high-fidelity Mermaid flowchart and conditional P2 design gate.
   • The 6 Personas & PoLP Delegation Matrix: Formally documents role boundaries, deliverables, metadata ownership, and runtime shell execution revocation for P1–P4.
   • Core Governance & Invariants: Details Rule 0 (JIT Issue-First), Rule 0.1 (Epic Branch Isolation), Rule A (Append-Only), WIP=1, Dual-Write, and Zero Auto-Merge Lock.
   • Repository Architecture: Complete annotated ASCII directory layout covering .agent/, docs/, scripts/, and app/.
   • Declarative Configuration: Full kernel.config.json snippet with schema validation explanation.
   • Quickstart & Pairing Workflow: 4-step developer onboarding and interaction walkthrough.
   • Technical Playbooks & Governance Registry: Comprehensive indexed catalog linking all playbooks, rules, and technical contracts.
   • Android Starter Stack & CI/CD: Details Jetpack Compose, Roborazzi screenshot testing, Kotlin progressive compiler, and GitHub Actions pipeline.

3. Runtime & Governance Hardening:

   • .agent/hooks/post-checkout: Replaced legacy # Second Brain header with # Agentic Android Delivery Kernel.
   • scripts/seal-issue.sh: Added safe bash variable escaping (escapeBash) to prevent command substitution errors when plan titles contain backticks or dollar signs.

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🛡️ Quality Airbag Verification

Verification Suite	Status	Execution Details
Documentation Contracts (validate-docs.sh)	✅ 38/38 Passing	Core contracts, personas (< 4,500 B), playbooks (< 8,500 B), rules (< 9,500 B), templates, and hooks verified.
Runtime Guardrails (test-runtime-guardrails.mjs)	✅ 20/20 Passing	Verified PoLP revocation for P1–P4, runtime rejection of --no-verify, hooks tampering (-c core.hooksPath), and protected branch writes.
Android Code Sanity (quality-check.sh)	✅ Passing (492ms)	Kotlin Progressive compiler, Java compiler (-Xlint:all), Android Lint Debug & Release, JVM Unit Tests & Roborazzi screenshot verification.
Pre-Commit Airbag Hook	✅ Passing	Executed automatically on commit 69633f9.

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🔍 Pre-Public Release Review Summary

• Secrets & Credentials: 100% clean; zero committed keys, keystores, or PII.
• Licensing: Apache-2.0 cleanly documented with root LICENSE.
• Branch Protection & CI: CI checks enforce Quality Airbag on main and epic/**.
• Zero Critical Blockers: Repository is fully hardened and ready for public presentation.