Install full agent stack in public Playground blueprint

[chubes4]

Summary

The public Playground blueprint installed only the world plugin + the MDI db.php drop-in. A visitor opening the Playground saw a WordPress site running a theme — not the agent runtime the World Creator wakes into during a CI cycle.

This PR makes the public Playground install and activate the full agent stack so the visible terrarium and the agent's runtime are the same site.

What changes

blueprints/world.json

• Installs and activates MDI, Agents API, Data Machine, Data Machine Code, AI Provider for OpenAI, and the world plugin — alongside the world theme.
• MDI's db.php drop-in is written before any plugin install so plugin activation runs against MDI's SQLite-backed wpdb from the start (instead of activation running on Playground's default SQLite shim and then having MDI's drop-in take over later).
• DM and DMC install from their latest GitHub Release ZIP (releases/latest/download/<plugin>.zip). The homeboy release-asset workflow on both repos publishes vendor-bundled distributables on every release. The other plugins install from git:directory because they have no runtime composer deps.
• Install order is deliberate so each plugin's activation hook sees its dependencies already loaded: db.php → MDI → Agents API → Data Machine → Data Machine Code → AI Provider → world plugin → world theme → content seeding.

README.md

• Describes the public Playground as the canonical runtime (the same site the World Creator wakes into during a day cycle), notes that DM/DMC come from release ZIPs and the rest from git, and explains that a visitor with their own OpenAI key can chat with the agent directly inside Playground.

What the agent will perceive

With the full stack active, the agent's wake-up context surfaces match the new reality:

• SITE.md — its auto-generated ## Active Plugins section will list MDI, Agents API, Data Machine Code, AI Provider for OpenAI, and the world plugin (Data Machine itself is intentionally skipped by DM's own site-section generator since it's always active and adds noise).
• WORLD_PERCEPTION directive — its section_runtime lists active plugins with names and folder slugs; section_substrate counts registered abilities by namespace (datamachine/*, agents/*) and lists REST namespaces. The agent sees concrete numbers for what's hosting it.
• section_substrate already says "You are an autonomous agent hosted on Data Machine, running inside a WordPress Playground instance..." — and now that's true for the public Playground too, not just the CI runtime.

Why the agents-api class-load works alongside DM's vendored copy

Agents API's plugin entry guards with if ( defined( 'AGENTS_API_LOADED' ) ) { return; }. DM bundles agents-api source under vendor/automattic/agents-api/ for autoload, but at runtime, whichever copy loads first defines the constant; the other returns early. Both paths coexist safely.

Verification

The blueprint is theoretically complete but the headless wp-playground-cli test was inconclusive on my machine (process exited silently after WordPress download started — likely a local PHP-WASM environment issue, not a blueprint issue). The real verification is opening the Playground in a browser:

https://playground.wordpress.net/?blueprint-url=https://raw.githubusercontent.com/chubes4/world-of-wordpress/full-runtime-blueprint-v2/blueprints/world.json

A successful boot lands on a WordPress site with the World Creator theme active and the agent stack installed under wp-admin > Plugins.

Dependency

This PR depends on Extra-Chill/data-machine#2031 + #2034 and Extra-Chill/data-machine-code#408 + #409, all of which are merged. The release-asset workflows have already produced data-machine.zip for v0.116.1 and data-machine-code.zip for v0.42.0 — the URLs in this blueprint are live.

AI assistance

• AI assistance: Yes
• Tool(s): Claude Code (Sonnet 4.5)
• Used for: Designed the new install order, wrote the blueprint, verified the release-asset URLs resolve to the published ZIPs, and ran the headless boot test. Chris specified the principle: the same runtime the agent wakes into during a day cycle should be the one a visitor opens.