API V3: Implement Structured Error Handling and Validation Tests

- Updated api_get_object and api_post_object to extract rich metadata (meta.details) from 400/500 responses.
- Enables frontend to bubble up specific DB schema, validation, and constraint errors for better debugging.
- Added 'V3 Hardening' section to /testing dashboard with automated tests for Permissive Mode and Structured Error extraction.

src/lib/ae_api/api_post_object.ts

@@ -164,19 +164,34 @@ export const post_object = async function post_object({
 
             if (!response.ok) {
                 if (response.status === 404) {
-                    console.warn('404 Not Found. Returning null.');
+                    if (log_lvl) {
+                        console.log('The response was a 404 not found "error". Returning null.');
+                    }
                     return null;
                 }
-                
-                const errorBody = await response.text();
-                console.error(`HTTP error! status: ${response.status}`, errorBody);
 
-                // Don't retry on client errors (400, 401, 403)
-                if (response.status >= 400 && response.status < 404) {
+                // FAIL FAST (Section 2D): Do not retry on Auth/Permission failures
+                if (response.status === 401 || response.status === 403) {
+                    console.error(`API Auth Failure (${response.status}). Failing fast as per Section 2D protocol.`);
                     return false;
                 }
 
-                throw new Error(`HTTP error! status: ${response.status} - ${errorBody}`);
+                // Structured Error Handling (V3): Attempt to get rich error metadata
+                let error_json: any = null;
+                try {
+                    error_json = await response.json();
+                } catch (e) {
+                    // Not JSON
+                }
+
+                if (log_lvl) console.log('The response was not ok. Structured Error Check:', error_json);
+                
+                if (error_json?.meta?.details) {
+                    // Return the rich error object so caller can handle specific categories (database_schema, etc)
+                    return error_json; 
+                }
+
+                throw new Error(`HTTP error! status: ${response.status}`);
             }
 
             if (!return_blob) {