feat: widen ai_provider_type enum for chatd providers (#25394)

coderd/database/migrations/000499_ai_provider_type_chatd_values.down.sql

@@ -0,0 +1,3 @@
+-- No-op: Postgres does not allow removing enum values safely.
+-- Matches the precedent in 000495_ai_providers.down.sql for ALTER
+-- TYPE resource_type / api_key_scope ADD VALUE.

coderd/database/migrations/000499_ai_provider_type_chatd_values.up.sql

@@ -0,0 +1,15 @@
+-- Widen ai_provider_type to carry the full chatd provider set so the
+-- chatd-side migration can preserve type fidelity when it lands. The
+-- aibridge runtime currently has native support only for OpenAI and
+-- Anthropic (with a Bedrock variant on the Anthropic client); the new
+-- non-Bedrock types route through the OpenAI fantasy client today
+-- because chatd already configures these providers against their
+-- OpenAI-compatible endpoints. Native gateway-side support for these
+-- providers comes later, at which point this enum already carries the
+-- right discriminator and no further migration is needed.
+ALTER TYPE ai_provider_type ADD VALUE IF NOT EXISTS 'azure';
+ALTER TYPE ai_provider_type ADD VALUE IF NOT EXISTS 'bedrock';
+ALTER TYPE ai_provider_type ADD VALUE IF NOT EXISTS 'google';
+ALTER TYPE ai_provider_type ADD VALUE IF NOT EXISTS 'openai-compat';
+ALTER TYPE ai_provider_type ADD VALUE IF NOT EXISTS 'openrouter';
+ALTER TYPE ai_provider_type ADD VALUE IF NOT EXISTS 'vercel';