aico 0.9.1

A patch on 0.9.0, for one thing that mattered to anyone installing the VS Code extension.

Fixed: npm install -g github:suhail-akhtar/aico#<tag> recursed until it failed.
The global install exports npm_config_global=true into every lifecycle script; the
prepare step that installs the web client's dependencies inherited it, and a global
install with no package named installs the current directory — the clone being
prepared. Six levels deep, then failure. npx github: never hit it, so the README's
headline path always worked; the global aico a VS Code user needs on their PATH
did not. The prepare script now scrubs the outer config from its children and refuses
to run nested. Verified: a global install into a clean prefix, exit 0, aico --version.

The site's VS Code page also pointed at npm install -g @suhail-akhtar/aico, which is
not on the registry. It and the README now say:

npm install -g github:suhail-akhtar/aico#v0.9.1

Everything in 0.9.0 — kept corrections, measured skills, server-side compaction —
is unchanged. Full notes: https://github.com/suhail-akhtar/aico/blob/main/CHANGELOG.md

The attached .vsix is the VS Code extension (0.6.1), unchanged since 0.9.0.