refactor(hooks): use provider_models mapping for image analysis

Changes ImageAnalysisConfig from providers array to provider_models
mapping for granular vision model control per CLIProxy provider.

Breaking change: config.yaml image_analysis section now uses
provider_models instead of providers/model fields.

Provider-to-model mappings:
- agy → gemini-2.5-flash
- gemini → gemini-2.5-flash
- codex → gpt-5.1-codex-mini
- kiro → kiro-claude-haiku-4-5
- ghcp → claude-haiku-4.5
- claude → claude-haiku-4-5-20251001

Hook checks CCS_CURRENT_PROVIDER against provider_models and skips
if no vision model configured for that provider.

lib/hooks/image-analyzer-transformer.cjs

@@ -6,12 +6,13 @@
  * Returns detailed text descriptions instead of allowing direct visual access.
  *
  * Environment Variables (set by CCS):
- *   CCS_IMAGE_ANALYSIS_SKIP=1           - Skip this hook entirely
- *   CCS_IMAGE_ANALYSIS_ENABLED=1        - Enable image analysis (default: 1)
- *   CCS_IMAGE_ANALYSIS_MODEL            - Model to use (default: gemini-2.5-flash)
- *   CCS_IMAGE_ANALYSIS_TIMEOUT=60       - Timeout in seconds (default: 60)
- *   CCS_PROFILE_TYPE                    - Profile type (account/default skip)
- *   CCS_DEBUG=1                          - Enable debug output
+ *   CCS_IMAGE_ANALYSIS_SKIP=1                 - Skip this hook entirely
+ *   CCS_IMAGE_ANALYSIS_ENABLED=1              - Enable image analysis (default: 1)
+ *   CCS_IMAGE_ANALYSIS_PROVIDER_MODELS        - Provider:model mapping (e.g., agy:gemini-2.5-flash,gemini:gemini-2.5-flash)
+ *   CCS_CURRENT_PROVIDER                      - Current CLIProxy provider (e.g., agy, gemini, codex)
+ *   CCS_IMAGE_ANALYSIS_TIMEOUT=60             - Timeout in seconds (default: 60)
+ *   CCS_PROFILE_TYPE                          - Profile type (account/default skip)
+ *   CCS_DEBUG=1                               - Enable debug output
  *
  * Exit codes:
  *   0 - Allow tool (pass-through to native Read)
@@ -65,6 +66,31 @@ Be comprehensive - this description replaces direct visual access.`;
 // HELPER FUNCTIONS
 // ============================================================================
 
+/**
+ * Parse provider_models env var to object
+ * Format: provider:model,provider:model
+ */
+function parseProviderModels(envValue) {
+  if (!envValue) return {};
+  const result = {};
+  envValue.split(',').forEach((pair) => {
+    const [provider, model] = pair.split(':');
+    if (provider && model) {
+      result[provider.trim()] = model.trim();
+    }
+  });
+  return result;
+}
+
+/**
+ * Get model for current provider from provider_models mapping
+ */
+function getModelForProvider() {
+  const currentProvider = process.env.CCS_CURRENT_PROVIDER || '';
+  const providerModels = parseProviderModels(process.env.CCS_IMAGE_ANALYSIS_PROVIDER_MODELS);
+  return providerModels[currentProvider] || DEFAULT_MODEL;
+}
+
 /**
  * Check if file is an analyzable image or PDF
  */
@@ -295,6 +321,11 @@ function shouldSkipHook() {
   const profileType = process.env.CCS_PROFILE_TYPE;
   if (profileType === 'account' || profileType === 'default') return true;
 
+  // Check if current provider has a vision model configured
+  const currentProvider = process.env.CCS_CURRENT_PROVIDER || '';
+  const providerModels = parseProviderModels(process.env.CCS_IMAGE_ANALYSIS_PROVIDER_MODELS);
+  if (!providerModels[currentProvider]) return true;
+
   return false;
 }
 
@@ -368,7 +399,7 @@ async function processHook() {
       process.exit(0);
     }
 
-    const model = process.env.CCS_IMAGE_ANALYSIS_MODEL || DEFAULT_MODEL;
+    const model = getModelForProvider();
     const timeout = parseInt(process.env.CCS_IMAGE_ANALYSIS_TIMEOUT || DEFAULT_TIMEOUT_SEC, 10);
     const timeoutMs = timeout * 1000;