Misc · Time: clocks and a stopwatch

misc::Clock shows the time in a zone, the system's unless told, as an
analog face with hour marks and three hands over its digits and a
label; it wakes its view at each whole second of the wall clock, and
only while the owner passes no moment. misc::WorldClock lays places in
rows: a small face, the place, how its day and hour stand against home,
and its time. misc::Stopwatch runs on the executor's clock in tenths,
holds while paused, marks laps while running and clears once paused;
Start and Pause share one button and its focus.

AGENTS.md

@@ -197,6 +197,7 @@ Ely GPUI Component. A component library for GPUI, in light and dark.
 - Color-blind safe charts swap Ely's chart hues for a set fitted to stay apart under Machado's protanopia, deuteranopia and tritanopia; a test holds every pair 0.10 apart in Oklab and each hue 3:1 on its page (`Theme::set_color_blind_safe`, in Ely's own palettes alone).
 - gpui 0.2.2's Metal renderer starts its instance buffer at 2 MB; a frame that outgrows it logs "failed to render … retrying with larger instance buffer size" and the buffer doubles, up to 256 MB. A world map's first frame grows it to 16 MB, then draws: the log is gpui's recovery, not a failure.
 - gpui 0.2.2 packs pictures in its atlas without padding and samples them with a linear filter, so a scaled picture's edge takes color from its atlas neighbor, and pictures laid edge to edge show seams. A map tile carries a one-pixel rim copied from its own edge and draws one of its pixels larger each side, clipped to its box (`maps::tile`).
+- A wall clock reads `Timestamp::now` and wakes its view at each whole second through a keyed task, only while the owner passes no moment; a stopwatch reads the executor's clock, so tests advance it (`misc::Clock`, `misc::Stopwatch`).
 - A map keeps places in `f64`: at zoom 19 the world is 134 million pixels across. Its wheel pans and Command or Control with the wheel zooms about the pointer, as the canvas's does. Its tiles stay in gpui's asset cache, as every `img()` picture does. Its popup is an overlay that is not modal: it takes focus when it shows, and the frame it stops showing, by any way out, hands focus back. Its layers, lines and areas unwrap across the date line and repeat on every world in view. Clustered pins gather by squares of the world, not of the view, so a pan never regroups them; a zoom may, so it hands a focused pin's or cluster's focus to the map.
 
 ## Decisions