Hatch the usage spent since the panel last showed each bar - #49

Description

When the panel opens, the part of each bar used up while it was closed blinks hatched (in the bar's own color) for 3.5 s, then the fill grows over it in 0.7 s and it counts as seen. Every progress bar of every provider, on the overview and the provider pages.

• Seen = the used percent a bar last showed in the open panel, kept in memory per plugin + line (use-unseen-usage.ts). A page switch keeps it; a restart starts from the first data.
• Kept in used terms, so switching used/left isn't spending. Showing what's left, the hatch is the piece the fill lost.
• A reset (usage going down from the last value it got, even while still above what was seen) isn't spending: it becomes the new start.
• The hatch is drawn while the panel is hidden too, so opening the panel doesn't first show the new fill and then take it back. The timers only run while it's open; closing it mid-blink keeps it for the next open, and more usage while it blinks starts it over from what was seen.
• Open is asked from the OS (getCurrentWindow().isVisible() on focus, blur and visibilitychange, one answer shared by all bars): the hidden panel's webview reports itself visible before its first show.
• Reduced motion: the hatch doesn't blink.

Type of Change

• New feature

Testing

• bunx tsc --noEmit, bun run test (1408 passed)
• New tests: the hook's whole flow (hidden, open, blink, settle, seen), a reset, closing mid-blink, more usage while blinking, no key; the bar's hatch and fill in both display modes; the card's wiring per plugin + line.
• Tried in a running dev build (with 5 fake unseen points per bar, removed before the commit): the log showed the panel open detected and the hatch started on the Claude bars; the owner looked at it and asked to ship.

Checklist

• My PR targets the main branch
• I did not introduce new dependencies without justification

🤖 Generated with Claude Code

https://claude.ai/code/session_01KHc1HaoK4c5kUmgtCmKuwT