feat: multi-tenant client configuration and CLI

[PAMulligan]

Summary

• Add per-client JSON config files in clients/ with JSON Schema validation and IDE autocomplete
• Add CLI (pnpm claudius) with init, validate, and snippet commands for managing client deployments
• Generate both embed snippet formats: window.ClaudiusConfig script method and <claudius-chat> web component
• No changes to widget or worker source code -- all client config is runtime via existing props

New files

• clients/_schema.json -- JSON Schema for client configs
• clients/example.json + example-system-prompt.md -- reference template
• scripts/cli.ts -- CLI entry point (init/validate/snippet)
• scripts/lib/config.ts -- Config loader and validator
• scripts/lib/snippet.ts -- Embed snippet generator
• scripts/lib/__tests__/ -- 48 tests (config, snippet, integration)

Test plan

• pnpm test:scripts -- 48 tests passing (config validation, snippet generation, integration)
• pnpm claudius init test-client -- scaffolds config + system prompt
• pnpm claudius validate example -- validates example config
• pnpm claudius snippet example -- generates both embed snippets
• Widget tests still pass (29 tests)

🤖 Generated with Claude Code

[cloudflare-workers-and-pages]

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