Add hybrid platform info: global default with per-annotation overrides

Backend:
- Add optional platform field to VLMResult for per-annotation overrides
- Add platform_override param to VLMService for cloud APIs/custom setups
- Platform is null by default (uses metadata default like RTX 4090)

Frontend:
- Add platform field to Annotation type for overrides
- Update AnnotationViewer to accept and display effective platform
- Show platform badge in annotation details when available
- Compute effectivePlatform: annotation override || global default

This enables future support for mixed-platform annotations (e.g., some
local GPU, some cloud inference) while keeping current behavior unchanged.

Ref #9

Author: claude

frontend/app/components/AnnotationViewer.tsx

@@ -1,14 +1,16 @@
 'use client'
 
 import { useState } from 'react'
-import { PromptAnnotation } from '../types'
+import { PromptAnnotation, PlatformInfo } from '../types'
 import { Copy, Check, FileText, FileJson, Activity, Zap } from 'lucide-react'
+import PlatformBadge from './PlatformBadge'
 
 interface AnnotationViewerProps {
   annotation: PromptAnnotation
+  platform?: PlatformInfo | null
 }
 
-export default function AnnotationViewer({ annotation }: AnnotationViewerProps) {
+export default function AnnotationViewer({ annotation, platform }: AnnotationViewerProps) {
   const [copied, setCopied] = useState(false)
   const [viewMode, setViewMode] = useState<'text' | 'json'>('text')
 
@@ -190,6 +192,14 @@ export default function AnnotationViewer({ annotation }: AnnotationViewerProps)
           )}
         </div>
       )}
+
+      {/* Platform info (shown inline with metrics) */}
+      {platform && (
+        <div className="flex items-center gap-2 mt-3">
+          <span className="text-xs text-agi-teal-500 dark:text-zinc-500">Platform:</span>
+          <PlatformBadge platform={platform} />
+        </div>
+      )}
     </div>
   )
 }

frontend/app/page.tsx

@@ -89,13 +89,23 @@ export default function Dashboard() {
     return []
   }, [annotations, selectedImageIndex, images, selectedModel])
 
+  // Get current model annotation (includes platform override if present)
+  const currentModelAnnotation = useMemo(() => {
+    if (!images[selectedImageIndex] || !selectedModel) return null
+    const imageAnnotations = annotations[images[selectedImageIndex].id] || []
+    return imageAnnotations.find(a => a.model === selectedModel) || null
+  }, [annotations, selectedImageIndex, images, selectedModel])
+
   // Get current prompt annotation
   const currentPromptAnnotation = useMemo(() => {
-    if (!images[selectedImageIndex] || !selectedModel || !selectedPromptKey) return null
-    const imageAnnotations = annotations[images[selectedImageIndex].id] || []
-    const modelAnnotation = imageAnnotations.find(a => a.model === selectedModel)
-    return modelAnnotation?.prompts[selectedPromptKey] || null
-  }, [annotations, selectedImageIndex, images, selectedModel, selectedPromptKey])
+    if (!currentModelAnnotation || !selectedPromptKey) return null
+    return currentModelAnnotation.prompts[selectedPromptKey] || null
+  }, [currentModelAnnotation, selectedPromptKey])
+
+  // Get effective platform (annotation override or default)
+  const effectivePlatform = useMemo(() => {
+    return currentModelAnnotation?.platform || platformInfo
+  }, [currentModelAnnotation, platformInfo])
 
   async function loadAnnotationsForImage(imageId: string) {
     setImageLoading(true)
@@ -307,7 +317,7 @@ export default function Dashboard() {
               </h3>
               <div className="flex-1 overflow-auto">
                 {currentPromptAnnotation ? (
-                  <AnnotationViewer annotation={currentPromptAnnotation} />
+                  <AnnotationViewer annotation={currentPromptAnnotation} platform={effectivePlatform} />
                 ) : (
                   <div className="text-agi-teal-500 dark:text-zinc-500 text-center py-8">
                     {!selectedModel ? 'Select a vision model to explore annotations' :

frontend/app/types.ts

@@ -29,6 +29,7 @@ export interface Annotation {
   model: string
   temperature?: number
   prompts: Record<string, PromptAnnotation>
+  platform?: PlatformInfo | null  // Override for this annotation (e.g., cloud API)
 }
 
 export interface GPUInfo {

src/image_annotation/services/vlm_service.py

@@ -10,7 +10,7 @@
 from langchain_ollama import ChatOllama
 from pydantic import BaseModel, Field
 
-from image_annotation.utils.platform_info import get_platform_info
+from image_annotation.utils.platform_info import PlatformInfo, get_platform_info
 
 
 class VLMPrompt(BaseModel):
@@ -67,6 +67,11 @@ class VLMResult(BaseModel):
 
     # Additional metadata
     temperature: float | None = None
+    platform: dict | None = Field(
+        None,
+        description="Platform info override for this annotation (e.g., cloud API). "
+        "If None, uses the default platform from metadata.",
+    )
 
 
 class VLMService:
@@ -78,6 +83,7 @@ def __init__(
         base_url: str = "http://localhost:11434",
         temperature: float = 0.3,
         timeout: int = 60,
+        platform_override: dict | None = None,
     ):
         """Initialize the VLM service.
 
@@ -86,11 +92,14 @@ def __init__(
             base_url: OLLAMA API base URL.
             temperature: Generation temperature.
             timeout: Request timeout in seconds.
+            platform_override: Optional platform info to use instead of auto-detection.
+                Useful for cloud APIs (OpenAI, Anthropic) or custom setups.
         """
         self.model = model
         self.base_url = base_url
         self.temperature = temperature
         self.timeout = timeout
+        self.platform_override = platform_override
         self._llm_cache = {}
 
     def _get_llm(self, model: str | None = None) -> ChatOllama:
@@ -289,6 +298,7 @@ def annotate_image(
                 performance_metrics=performance_metrics,
                 temperature=self.temperature,
                 error=error,
+                platform=self.platform_override,  # Include if set (for cloud APIs, etc.)
             )
 
         except Exception as e:
@@ -305,6 +315,7 @@ def annotate_image(
                 performance_metrics=PerformanceMetrics(total_duration_ms=total_time_ms),
                 temperature=self.temperature,
                 error=str(e),
+                platform=self.platform_override,
             )
 
     def annotate_batch(