Simplify owner dashboard lead workflow

[DevCalebR]

Summary

• Carries forward the existing owner-safe setup cleanup on this branch.
• Refactors the owner dashboard around missed-call lead follow-up instead of technical setup or revenue/demo framing.
• Keeps /app/leads as a scoped inbox/list and makes /app/leads/[leadId] the primary action workspace for calling, reviewing conversations, and marking contacted/booked/lost.
• Simplifies /app/conversations into a conversation index that deep-links directly to the matching lead detail page.
• Preserves owner alert deep links to /app/leads/[leadId] and strengthens regression coverage for tenant safety and customer-visible language.

Tenant and owner-safety checks

• Customer-visible pages avoid Twilio, A2P, provisioning, SID, webhook, admin, and setup-control terminology.
• Lead inbox and detail routes remain business-scoped through the existing requireBusiness and business-id data access patterns.
• Status actions remain protected by business-scoped updates.

Validation

• ./node_modules/.bin/tsx --test tests/customer-home-dashboard.test.ts tests/leads-workspace-routing.test.ts tests/tenant-isolation-wiring.test.ts tests/tenant-isolation.test.ts tests/owner-notification-idempotency.test.ts tests/pilot-safety.test.ts
• npm run env:check
• npm run preflight:providers
• npm run typecheck
• npm run lint
• npm run test
• npm run build