Restore custom DB types and fix downstream type issues

Restored hand-maintained database types and improved JSONB compatibility — Replaced the custom types that were accidentally overwritten during a generated types regen. Restored enum aliases (LLM providers, changelog entry types, entitlement types, etc.), corrected webhook event values, and updated changelog JSON interfaces so changelog content can be stored directly in JSONB columns without extra casting.

Restored hand-maintained database types (enums and aliases) that were overwritten by generated types to keep DB constraints and code aligned.database
Made changelog JSON interfaces (diff summaries and generated JSON shapes) directly compatible with JSONB storage to avoid manual casting and runtime surprises.database
Added @supabase/supabase-js to the web app dependencies to support the branding upload route.frontend
Widened the changelogTheme variable to a plain string in the changelog layout to avoid type-related rendering issues.frontend

Fixed owner_type widening (was widened to string by generated types) by adding explicit casts where needed; addressed priority resolution and access checks in API routes, web pages, and background workers to prevent runtime errors.backend
Adjusted permission baseline lookup to cast clerk_role correctly so role-based permission checks evaluate reliably.auth
Removed an unused import in a background job to clean up build warnings.backend