Migrate the internal model from single-active scalar to multi-active
open_order array + per-id window records. register accepts opts.layout
(11 named slots: center, left, right, top, bottom, the four corners,
left-half, right-half — plus a custom function(sw,sh)->{x,y,w,h} hook
for HP-bars and bespoke positioning). open/close/is_open accept an
optional id argument for per-id semantics; the no-arg forms preserve
the v0.1.1 contract (close() removes the focused last-opened, is_open()
returns true if any panel is open).
Input dispatch iterates open_order in reverse so the topmost panel gets
the first crack at a click; misses fall through to lower windows.
is_pausing now checks every open window for pause_on_open=true, not
just the focused one.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Renders an X glyph in the top-right of every panel's title bar; left-
click on it calls M.close(). Hit-test in _dispatch_event runs before
the widget-forward path so the click is consumed by the panel-frame
even when a widget would otherwise handle it. Pairs with the existing
ESC-close-pattern that lives at module level.
Previously trigger_action_name + trigger_widget_id were module-local
scalars, so the second bind_default_trigger call overwrote the first
(and reused the action name 'panel_toggle' so lib-core.input's binding
was also clobbered). Switched to a triggers array; each binding gets
a unique input action 'panel_toggle_<widget_id>' so multiple widgets
can be toggled by their own keys independently.
_dispatch_event captures M at closure-definition time; with M declared
further down the file, the capture resolved to global M (nil), causing
'attempt to index a nil value (global M)' every frame the panel was open
and a mouse event was dispatched. Hoisting the table declaration above
the dispatch helpers fixes the resolution at compile time.
