fix: backfill legacy Bedrock AI provider rows and stale model config strings (#26155)

Fixes CODAGT-548

Adds two idempotent startup backfills run after `newAPI():

- `BackfillBedrockProviderType`: promotes `ai_providers` rows from
`type=anthropic` with Bedrock settings to `type=bedrock`.
- `BackfillChatModelConfigProviderStrings`: fixes stale
`chat_model_configs.provider = "anthropic"` strings on rows whose linked
provider was just promoted.
- `UpdateAIProvider` query now also writes the `type` column, so the
fix persists on any subsequent PATCH.


> 🤖 Generated by Claude with oversight from a human.

cli/server.go

@@ -1048,6 +1048,11 @@ func (r *RootCmd) Server(newAPI func(context.Context, *coderd.Options) (*coderd.
 			); err != nil {
 				return xerrors.Errorf("seed ai providers from env: %w", err)
 			}
+			// Must run after newAPI so options.Database is dbcrypt-wrapped.
+			coderd.BackfillBedrockProviderType(aibridgeInitCtx, options.Database, logger.Named("aibridge.backfill"))
+			// Must run after BackfillBedrockProviderType; shares aibridgeInitCtx so
+			// a timeout on the first backfill will skip this one until next startup.
+			coderd.BackfillChatModelConfigProviderStrings(aibridgeInitCtx, options.Database, logger.Named("aibridge.backfill"))
 
 			// In-memory aibridge daemon. Registered on coderd so chatd can
 			// dispatch LLM requests via the in-process transport without