fix(model-core): fix duplicate DeepSeek declarations and broken exports

Restored the original model-family-detectors.ts from upstream (which
had isGlmModel and isGeminiModel that were accidentally deleted).
Added DeepSeek V4 functions correctly after isMiniMaxModel.

Fixed TS error in deepseek-v4.ts: buildTaskManagementSection takes
1 argument (useTaskSystem boolean), not 2.

Author: EvangelosMoschou

packages/model-core/src/model-family-detectors.ts

@@ -75,7 +75,6 @@ export function isMiniMaxModel(model: string): boolean {
   const modelName = extractModelName(model).toLowerCase()
   return modelName.includes("minimax")
 }
-
 export function isDeepSeekV4Model(model: string): boolean {
   const modelName = extractModelName(model).toLowerCase().replaceAll("_", "-").replaceAll(".", "-")
   return modelName.includes("deepseek") && /v[_-]?4/.test(modelName)
@@ -89,18 +88,6 @@ export function isDeepSeekV4FlashModel(model: string): boolean {
   return isDeepSeekV4Model(model) && extractModelName(model).toLowerCase().includes("flash")
 }
 
-export function isDeepSeekV4Model(model: string): boolean {
-  const modelName = extractModelName(model).toLowerCase().replaceAll("_", "-").replaceAll(".", "-")
-  return modelName.includes("deepseek") && /v[_-]?4/.test(modelName)
-}
-
-export function isDeepSeekV4ProModel(model: string): boolean {
-  return isDeepSeekV4Model(model) && extractModelName(model).toLowerCase().includes("pro")
-}
-
-export function isDeepSeekV4FlashModel(model: string): boolean {
-  return isDeepSeekV4Model(model) && extractModelName(model).toLowerCase().includes("flash")
-}
 
 export function isGlmModel(model: string): boolean {
   const modelName = extractModelName(model).toLowerCase()

packages/omo-opencode/src/agents/sisyphus/deepseek-v4.ts

@@ -48,7 +48,7 @@ export function buildDeepSeekV4SisyphusPrompt(
   useTaskSystem = false,
 ): string {
   const toolsDisplay = tools.map((t) => t.name).join(", ")
-  const taskSection = buildTaskManagementSection(agents, useTaskSystem)
+  const taskSection = buildTaskManagementSection(useTaskSystem)
   const isPro = model.toLowerCase().includes("pro")
 
   return `\n<identity>