fix: resolve review issues - remove duplicate OpenRouter fallback utils, preserve Bedrock opt-in caching default

- openrouter.ts: Remove inline firstNumber/toFiniteNumber fallback chains that
  duplicated the profile-based resolution in usage-profiles.ts. Now uses simple
  totalUsage ?? usage preference and delegates all further extraction to
  normalizeProviderUsage.

- bedrock.ts: Preserve historical opt-in caching default. Previously controlled
  by awsUsePromptCache (defaulting to off), the migration to unified
  promptCachingEnabled (defaulting to true) silently enabled caching for
  existing Bedrock users. Now explicitly defaults to false for Bedrock when
  no global setting exists.

src/api/providers/bedrock.ts

@@ -252,6 +252,15 @@ export class AwsBedrockHandler extends BaseProvider implements SingleCompletionH
 			}
 		}
 
+		// Bedrock caching was historically opt-in (awsUsePromptCache).
+		// Preserve that default: when no explicit global or provider-level
+		// setting exists, default to disabled so existing users are not
+		// silently enrolled.
+		const bedrockCacheSettings = {
+			...this.options,
+			promptCachingEnabled: this.options.promptCachingEnabled ?? false,
+		}
+
 		const promptCache = applyPromptCacheToMessages({
 			adapter: "bedrock",
 			overrideKey: "bedrock",
@@ -260,7 +269,7 @@ export class AwsBedrockHandler extends BaseProvider implements SingleCompletionH
 				supportsPromptCache: modelConfig.info.supportsPromptCache,
 				promptCacheRetention: modelConfig.info.promptCacheRetention,
 			},
-			settings: this.options,
+			settings: bedrockCacheSettings,
 		})
 
 		// Build streamText request

src/api/providers/openrouter.ts

@@ -30,7 +30,6 @@ import { getModelEndpoints } from "./fetchers/modelEndpointCache"
 import { applyRouterToolPreferences } from "./utils/router-tool-preferences"
 import { generateImageWithProvider, ImageGenerationResult } from "./utils/image-generation"
 import { normalizeProviderUsage } from "./utils/normalize-provider-usage"
-import { toFiniteNumber, firstNumber } from "./utils/usage-metrics"
 
 import type { ApiHandlerCreateMessageMetadata, SingleCompletionHandler } from "../index"
 import type { ApiStreamChunk } from "../transform/stream"
@@ -180,26 +179,14 @@ export class OpenRouterHandler extends BaseProvider implements SingleCompletionH
 
 			const usage = await result.usage
 			const totalUsage = await result.totalUsage
-			const rawUsage = (usage as any)?.raw as Record<string, unknown> | undefined
 
+			// Prefer totalUsage (multi-step accumulation) over per-step usage;
+			// all further fallback extraction is handled by the openrouter profile
+			// in usage-profiles.ts via normalizeProviderUsage.
 			const usageRecord = {
 				...(usage as any),
-				inputTokens: firstNumber([
-					totalUsage.inputTokens,
-					(usage as any).inputTokens,
-					(usage as any).promptTokens,
-					(usage as any).prompt_tokens,
-					rawUsage?.prompt_tokens as number | undefined,
-					rawUsage?.input_tokens as number | undefined,
-				]),
-				outputTokens: firstNumber([
-					totalUsage.outputTokens,
-					(usage as any).outputTokens,
-					(usage as any).completionTokens,
-					(usage as any).completion_tokens,
-					rawUsage?.completion_tokens as number | undefined,
-					rawUsage?.output_tokens as number | undefined,
-				]),
+				inputTokens: totalUsage.inputTokens ?? (usage as any).inputTokens,
+				outputTokens: totalUsage.outputTokens ?? (usage as any).outputTokens,
 			}
 			const { chunk } = normalizeProviderUsage({
 				provider: "openrouter",