Give plugins access to device-wide config, and a global scroll frame rate (#424)

* Give plugins access to device-wide config, and a global scroll frame rate

The sports scoreboards read `getattr(self, 'global_config', {})` to find a
shared scroll frame rate, but nothing ever set that attribute: the loader
constructs plugins with only plugin_id/config/display_manager/cache_manager/
plugin_manager (plugin_loader.py:671), `global_config` appears nowhere in
src/, no plugin manager assigns it, and BasePlugin has no __getattr__ to
synthesize it. The lookup always returned {}, so the ten scroll_display.py
copies that thread target_fps through to ScrollHelper could never fire on any
core. There was also no global target_fps to find -- the only one in the
template is display.vegas_scroll.target_fps, which is Vegas-scoped.

Adds the missing half:

- `BasePlugin.global_config` resolves the full config via
  plugin_manager.config_manager, then cache_manager.config_manager, then {}.
  Same order the sports timezone helpers already use. Exceptions are swallowed
  to debug so an unreadable config can never stop a plugin loading, and a
  non-dict result is rejected rather than handed to callers that will .get()
  it and feed the result to numeric code.
- A top-level `target_fps` (default 100), exposed on the General tab and
  validated 30-200 on save to match ScrollHelper.set_target_fps -- which
  clamps silently, so a rejected save reports a value that would otherwise
  appear to save and then behave differently.

The property has a setter deliberately. news, stock-news, ledmatrix-stocks,
ledmatrix-elections, ledmatrix-leaderboard and nfl-draft all assign
`self.global_config = config.get('global', {})`; without a setter that raises
"property has no setter" and those six plugins stop loading. Reproduced, then
pinned with a test.

target_fps is also kept out of the `is_general_update` key list: that branch
treats a missing web_display_autostart as an unchecked box, so counting a
target_fps-only POST as a General save would silently switch autostart off.

Verified end to end: config.json -> BasePlugin.global_config ->
scroll_display's existing block -> ScrollHelper.target_fps 120 -> 100, with no
plugin-side change needed. Suite 1441 passed; the 4 failures
(test_display_dirty_tracking, test_web_api::test_get_system_status, two in
test_state_reconciliation) are pre-existing and reproduce identically on a
clean tree.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KEZK1P1Q1fu5pcuVrkrCFZ

* Address review findings on target_fps validation and config resolution

- Reject floats and bools before int() in the target_fps save path. A JSON
  body can carry them, where int(90.5) silently stored 90 and true stored 1.
  Form posts send strings, so '90.5' already failed in int().
- Assert the template's target_fps is 100, not merely an int, so the
  documented default is actually pinned.
- Empty-config precedence: keeping the `and config` check deliberately, now
  spelled out in the comment and covered by a test. Both managers default to
  the same config/config.json, so falling through cannot pick up a different
  file's settings; treating {} as an answer would instead return {} when the
  first manager simply hasn't loaded yet, silently disabling every setting
  read through the property -- the failure this property exists to fix.

Suite 1446 passed. The float-rejection test was checked to fail without the
guard.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KEZK1P1Q1fu5pcuVrkrCFZ

---------

Co-authored-by: Claude Sonnet 5 <noreply@anthropic.com>

src/plugin_system/base_plugin.py

@@ -145,6 +145,77 @@ class BasePlugin(ABC):
         """
         raise NotImplementedError("Plugins must implement display()")
 
+    # -------------------------------------------------------------------------
+    # Global (whole-device) configuration
+    # -------------------------------------------------------------------------
+    @property
+    def global_config(self) -> Dict[str, Any]:
+        """
+        The full LEDMatrix configuration, for reading device-wide settings.
+
+        ``self.config`` is only this plugin's own slice, so cross-cutting
+        settings — ``target_fps``, ``timezone``, ``location`` — were previously
+        unreachable from a plugin without reaching into a manager by hand.
+
+        Resolution order mirrors the timezone helpers the sports plugins
+        already ship: ``plugin_manager.config_manager`` first (the cores that
+        hang it there), then ``cache_manager.config_manager``. Returns ``{}``
+        when neither is available, so callers can use plain ``.get()`` without
+        guarding, and a plugin on a core that predates this property still
+        loads — ``getattr(self, 'global_config', {})`` simply yields the
+        default.
+
+        Treat as read-only: the returned dict is the live config the core is
+        using, so mutating it edits every other consumer's view and can be
+        persisted back to disk.
+
+        Assignment is still allowed and wins over the resolved value. Several
+        shipped plugins (news, stock-news, ledmatrix-stocks, ledmatrix-
+        elections, ledmatrix-leaderboard, nfl-draft) set
+        ``self.global_config`` to their own ``config['global']`` sub-dict; a
+        property without a setter would raise AttributeError and stop those
+        plugins loading.
+
+        Example:
+            fps = self.global_config.get('target_fps')
+        """
+        override = getattr(self, '_global_config_override', None)
+        if override is not None:
+            return override
+        for owner in (self.plugin_manager, self.cache_manager):
+            config_manager = getattr(owner, 'config_manager', None)
+            if config_manager is None:
+                continue
+            try:
+                config = config_manager.get_config()
+            except Exception:
+                # A broken or unreadable config must never stop a plugin from
+                # loading; fall through to the next source, then to {}.
+                self.logger.debug(
+                    "Could not read global config from %s",
+                    type(owner).__name__, exc_info=True,
+                )
+                continue
+            # Only a real mapping is usable: callers do .get() on this and feed
+            # the result to numeric code, so handing back whatever a stub or a
+            # half-built manager returned would fail later and further away.
+            #
+            # An empty dict is treated as "nothing here yet" rather than a
+            # valid answer, so resolution continues to the next source. Both
+            # managers default to the same config/config.json, so falling
+            # through cannot pick up a different file's settings -- but it does
+            # rescue the case where the first manager simply hasn't loaded yet,
+            # which would otherwise return {} and silently disable every
+            # setting read through this property.
+            if isinstance(config, dict) and config:
+                return config
+        return {}
+
+    @global_config.setter
+    def global_config(self, value: Dict[str, Any]) -> None:
+        """Let a plugin substitute its own view (see the getter's docstring)."""
+        self._global_config_override = value
+
     # -------------------------------------------------------------------------
     # Adaptive layout support (opt-in)
     # -------------------------------------------------------------------------