refactor(web): drop the two dead client-side config-form renderers

generateConfigForm and generateSimpleConfigForm (580 lines) were defined
on the Alpine component and never called: server-side Jinja replaced them,
as pages_v3.py:641 records. Nothing in any template invokes them -- there
is no x-html in the templates and no bracket access on the component.

They carried their own x-widget dispatch, which made them an active trap:
the next person adding a widget would reasonably think both renderers
needed updating.

plugins/config_manager.js (PluginConfigManager, 133 lines) goes for the
same reason -- loaded on every page from base.html, referenced only by
itself and by an archived doc.

Kept, having checked them: widgets/example-color-picker.js is the worked
example docs/widget-guide.md points plugin authors at, and
widgets/plugin-loader.js is the client half of a documented feature
(manifest-declared plugin widgets) whose server route is missing --
soccer-scoreboard already ships a widgets/custom-leagues.js that this
loader is meant to fetch. That is an unfinished feature to complete, not
dead code to delete.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

web_interface/static/v3/js/plugins/config_manager.js

@@ -1,133 +0,0 @@
-/**
- * Plugin configuration form management.
- * 
- * Handles configuration form generation, validation, and submission.
- */
-
-const PluginConfigManager = {
-    /**
-     * Current plugin configuration state.
-     */
-    currentState: {
-        pluginId: null,
-        config: null,
-        schema: null,
-        jsonEditor: null
-    },
-    
-    /**
-     * Initialize configuration for a plugin.
-     * 
-     * @param {string} pluginId - Plugin identifier
-     * @returns {Promise<Object>} Configuration and schema
-     */
-    async initialize(pluginId) {
-        try {
-            const [config, schema] = await Promise.all([
-                window.PluginAPI.getPluginConfig(pluginId),
-                window.PluginAPI.getPluginSchema(pluginId)
-            ]);
-            
-            this.currentState = {
-                pluginId,
-                config,
-                schema,
-                jsonEditor: null
-            };
-            
-            return { config, schema };
-        } catch (error) {
-            if (window.errorHandler) {
-                window.errorHandler.displayError(error, `Failed to initialize config for ${pluginId}`);
-            }
-            throw error;
-        }
-    },
-    
-    /**
-     * Reset configuration to defaults.
-     * 
-     * @param {string} pluginId - Plugin identifier
-     * @returns {Promise<Object>} Default configuration
-     */
-    async resetToDefaults(pluginId) {
-        try {
-            const result = await window.PluginAPI.resetPluginConfig(pluginId);
-            
-            // Reload configuration
-            if (this.currentState.pluginId === pluginId) {
-                await this.initialize(pluginId);
-            }
-            
-            return result;
-        } catch (error) {
-            if (window.errorHandler) {
-                window.errorHandler.displayError(error, `Failed to reset config for ${pluginId}`);
-            }
-            throw error;
-        }
-    },
-    
-    /**
-     * Save configuration.
-     * 
-     * @param {string} pluginId - Plugin identifier
-     * @param {Object} config - Configuration data
-     * @returns {Promise<Object>} Save result
-     */
-    async save(pluginId, config) {
-        try {
-            const result = await window.PluginAPI.savePluginConfig(pluginId, config);
-            
-            // Update local state
-            if (this.currentState.pluginId === pluginId) {
-                this.currentState.config = config;
-            }
-            
-            return result;
-        } catch (error) {
-            if (window.errorHandler) {
-                window.errorHandler.displayError(error, `Failed to save config for ${pluginId}`);
-            }
-            throw error;
-        }
-    },
-    
-    /**
-     * Validate configuration against schema.
-     * 
-     * @param {Object} config - Configuration data
-     * @param {Object} schema - JSON schema
-     * @returns {Object} Validation result with errors
-     */
-    validate(config, schema) {
-        // Basic validation - full validation happens on server
-        const errors = [];
-        
-        if (!schema || !schema.properties) {
-            return { valid: true, errors: [] };
-        }
-        
-        // Check required fields
-        if (schema.required) {
-            for (const field of schema.required) {
-                if (!(field in config)) {
-                    errors.push(`Required field '${field}' is missing`);
-                }
-            }
-        }
-        
-        return {
-            valid: errors.length === 0,
-            errors: errors
-        };
-    }
-};
-
-// Export
-if (typeof module !== 'undefined' && module.exports) {
-    module.exports = PluginConfigManager;
-} else {
-    window.PluginConfigManager = PluginConfigManager;
-}
-