feat(conjure): add the conjure plugin

[eric-factory]

What

Publishes the conjure skill as a marketplace plugin, so people get it without running conjure init.

Today the skill only reaches someone who already has the binary and runs conjure init in a folder with no index.html (it aborts otherwise). It lands in that one folder, frozen at whatever version the binary held. One copy in the wild was already 15 days and two login fixes behind the source, with nothing to signal it.

Contents

• plugins/conjure/ with plugin.json, README.md, and skills/conjure/SKILL.md
• skills/conjure symlink, per the convention check-skills enforces
• One entry in .factory-plugin/marketplace.json and a section in the root README.md

Two things worth a reviewer's attention

1. This also deletes skills/wiki. That symlink points at ../plugins/droid-evolved/skills/wiki, whose target was removed in #14. check-skills walks every link in skills/, so master is already failing and this PR could not go green next to it. Unrelated to the plugin; called out rather than buried.

2. The SKILL.md here is a copy. The source of truth is internal/cli/scaffold_skill.md in Factory-AI/conjure, where it is also embedded in the CLI. A companion PR there adds a workflow that opens a sync PR here whenever it changes. plugins/conjure/README.md says so, because an edit made here looks reasonable and would be silently overwritten.

Public-repo check

This marketplace is public, so the content was reviewed for exposure: no credentials, no internal hostnames beyond conjure.factory.ai and downloads.factory.ai (both already public; the CLI binaries are served unauthenticated), and the only warehouse example queries a table called wh_test. Conjure is Okta-gated, so the skill is useful only to Factory employees, but nothing in it is sensitive.

Verified

check-skills replicated locally against this branch: PASS (and reproduced the pre-existing failure on master).

Part of AUT-1829

[eric-factory]

Closing: the conjure plugin is going to Factory-AI/factory-internal-plugins instead.

factory-plugins is public, and Eno would rather this skill not be on the open web. The new repo is the internal counterpart, set up the same way, and the plugin is live there and verified installing end to end.

Two marketplaces shipping a skill with the same name: conjure would collide by name, so this copy should not land.

One thing here was not about conjure and is worth keeping: this PR also deleted the dangling skills/wiki symlink, which points at plugins/droid-evolved/skills/wiki and no longer exists. check-skills fails on it, so master is currently red and any PR opened against this repo inherits that failure. Someone should remove it separately.

Branch eric/aut-1829-conjure-plugin is left in place.