Fix/plugin module namespace collision (#229)

* fix(web): handle string boolean values in schedule-picker widget

The normalizeSchedule function used strict equality (===) to check the
enabled field, which would fail if the config value was a string "true"
instead of boolean true. This could cause the checkbox to always appear
unchecked even when the setting was enabled.

Added coerceToBoolean helper that properly handles:
- Boolean true/false (returns as-is)
- String "true", "1", "on" (case-insensitive) → true
- String "false" or other values → false

Applied to both main schedule enabled and per-day enabled fields.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix: trim whitespace in coerceToBoolean string handling

* fix: normalize mode value to handle per_day and per-day variants

* fix(plugins): resolve module namespace collisions between plugins

When multiple plugins have modules with the same name (e.g., data_fetcher.py),
Python's sys.modules cache would return the wrong module. This caused plugins
like ledmatrix-stocks to fail loading because it imported data_fetcher from
ledmatrix-leaderboard instead of its own.

Added _clear_conflicting_modules() to remove cached plugin modules from
sys.modules before loading each plugin, ensuring correct module resolution.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

---------

Co-authored-by: Chuck <chuck@example.com>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

web_interface/static/v3/js/widgets/schedule-picker.js

@@ -114,6 +114,18 @@
         return Boolean(value);
     }
 
+    /**
+     * Normalize mode value to handle both 'per_day' and 'per-day' variants.
+     */
+    function normalizeMode(mode) {
+        if (!mode || typeof mode !== 'string') {
+            return 'global';
+        }
+        // Normalize: replace hyphens with underscores and check for per_day
+        const normalized = mode.trim().toLowerCase().replace(/-/g, '_');
+        return normalized === 'per_day' ? 'per_day' : 'global';
+    }
+
     /**
      * Merge user value with defaults
      */
@@ -125,7 +137,7 @@
 
         const schedule = {
             enabled: coerceToBoolean(value.enabled),
-            mode: value.mode === 'per_day' ? 'per_day' : 'global',
+            mode: normalizeMode(value.mode),
             start_time: value.start_time || defaults.start_time,
             end_time: value.end_time || defaults.end_time,
             days: {}