Add media components 346-365; input.SlideBase, guarded Pad

An audio player with transport, scrubber and volume; an equalizer and
a visualizer; a playlist; a cassette, cartridge and record that turn
while they play and hold where they stop; piano keys, a step sequencer
and a tracker you can type into; a waveform, a 16:9 video frame, an
image compare, a gallery, a filmstrip, a record button and an FM tuner.

input exports SlideBase, the undrawn rail its sliders share; the
gallery treats exported Bases as building blocks, not components.
pixel's micro font gains '#' for notes like C#4. pixel.Pad and the
slide rail read input only while their base is enabled, so Inert or a
fresh Disabled stops a drag or a key already sent. AGENTS records why
a drawn container keeps the DISABLED description: MyGo paints a
disabled subtree at half opacity.

pixel/micro.go

@@ -52,6 +52,7 @@ var micro = microFont(map[rune]string{
 	'Z': "###|..#|.#.|#..|###",
 	'+': "...|.#.|###|.#.|...",
 	'-': "...|...|###|...|...",
+	'#': "#.#|###|#.#|###|#.#",
 	'.': "...|...|...|...|.#.",
 	':': "...|.#.|...|.#.|...",
 	'/': "..#|..#|.#.|#..|#..",