v0.1.6 — Billing, Chat improvements & Cloud deploy

Billing

• Confirmation dialogs on plan changes and cancellations
• "Scheduled – takes effect [date]" badge on plans with a pending downgrade
• Return notice after Stripe Portal session

Chat & Extraction

• Expandable tool call trace with full request/response detail
• Markdown tables rendered in chat
• Dashboard sidebar shows which sifts are used by each widget

Document pipeline

• Fix: org_id persisted on all documents (was causing 404 on document detail page)
• Stop indexing button: cancel all pending queue items for a sift

LLM & Configuration

• SIFTER_DEFAULT_BASE_URL propagated to all acompletion calls
• Vertex AI / Gemini: correctly skip api_key / api_base for native credentials

Auth & Privacy

• Privacy policy acceptance on registration
• Cascade account deletion
• Transactional email support via SMTP

Cloud & Deploy

• SDK default API URL changed to api.sifter.run
• VITE_API_URL support for Cloudflare Pages deployments (decoupled frontend/backend)