Add Ghost of AriPerkkio

[Karthikeyan1508]

Adds the Ghost of AriPerkkio bot: a Storybook PR reviewer channeling AriPerkkio's eye for test coverage, error handling, and story coverage in storybookjs/storybook.

• Repo fit: requires a storybookjs/storybook checkout with gh CLI access; read-only, paste-a-diff workflow.
• Permission mode: plan (reads and reasons, never edits) — safe by construction on a stranger's machine.
• Agent changed from the local codex record to claude-code so the explicit read-only tool fence (Read/Grep/Glob, gh/git-log/git-diff only) is enforceable; codex supports no allow/deny lists.
• Setup: one check-only step (gh auth status), no machine changes.
• Tested: validated against schema/bot.schema.json (slug match, enums, uniqueness, 498-word instructions limit, no machine-local leakage); working tree touches only bots/ghost-of-ariperkkio/.

Transparency note: persona drawn from 7 comments across 2 PRs, disclosed in the about field as a specialized lens rather than a full resurrection.