docs(readme): refresh homepage to house brand structure

[bgorzelic]

What changed

Visual refresh of the README to match the house brand structure used across the other repos (spookyjuice.ai, spookywrt, gmail-cleanup, etc.). No content rewrite -- the existing copy and tables are kept; the page is reordered and decorated with verifiable proof up front.

• Badge row under the value line: CI (real ci-typescript.yml workflow), npm version (published @bgorzelic/ghostlink@0.1.0), TypeScript strict, Node >= 18 (.nvmrc/engines), tests (108 -- verified by running the suite), ISC license (LICENSE file).
• First successful action near the top: an npx -y @bgorzelic/ghostlink .mcp.json snippet (the published package exposes the ghostlink bin, so this is mechanically valid), followed immediately by the real ToolEnvelope JSON as proof before the long explanation.
• Architecture promoted above Quick Start and the ASCII layer stack converted to a small mermaid diagram (same four layers, same file paths).
• Client Configuration compressed: three near-identical JSON blocks collapsed into one source-checkout block plus a client/location table. All headings kept, so existing anchors still resolve.

Why

The README had strong copy but buried the proof and the fastest install path below two screens of explanation, and repeated the same config block three times. This brings it in line with the proof-before-explanation structure of the other repo homepages and makes it shorter (76 insertions / 90 deletions).

Facts

No facts were added or invented. Every badge and claim was verified against the repo before inclusion: the test count by running npm test (108 passed), the npm badge against the live registry, the envelope shape against src/types/envelope.ts, and the audit-log table against src/core/logging/audit.ts.