Draw the terminal at the size of the pane it is in

[Alexgodoroja]

The terminal did not fill its pane

A viewer never changes how many columns and rows a session has — the relay picks the grid, the CLI opens the PTY at it. What a viewer chooses is how large to draw them, and that was a single knob: the font size, scaled until the grid fitted in whichever direction ran out first.

A pane is almost never the shape of a 120x36 grid, so on a wide one the columns stopped growing the moment the rows reached the bottom. Measured in a real layout at four window sizes, the grid used only 68–77% of the pane's width, and the text was a third smaller than there was room for.

window	before	after
1440x900	11.5px, 77% of the width	14.75px, 98%
1728x1000	13.5px, 71%	17.75px, 94%
1920x1080	14.75px, 68%	19.75px, 91%
2560x1440	21.25px, 70%	28.25px, 93%

What changed

fittedTerminal replaces fittedTerminalFontSize and returns two things instead of one:

• The font comes from the width, where the columns are.
• The rows are then spread down the full height with whatever leading is left over, between the font's own line box and the leading the surface asked for (1.35 in the app, the device's typography in the standalone viewer). A pane with height to spare keeps the leading it had.

Neither axis may overflow. The size is derived from what the browser says a character measures, then checked against what the emulator will actually lay out — columns rounded to whole CSS pixels, rows to whole device pixels at the ratio the screen will round to — and stepped down if it would not fit. A test sweeps 126 box/ratio combinations and asserts the drawn grid never exceeds the box.

All of it is client-side: no session, no relay and no PTY sees any of this.

Supporting changes:

• web/terminal-metrics.ts, vendored into the app beside the fit and covered by npm run check:protocol, holds the two browser measurements — what a character occupies (the way xterm measures it, so the chosen size is the size that lands) and how much room the pane has, minus a scrollbar only where the platform actually takes one.
• What the fit cannot use is now split between both sides of the pane instead of left down one of them.
• Measuring directly retires FitAddon in the viewer, where proposeDimensions was the only thing it was used for. The app still ships it for the sign-in page's animated preview, which genuinely wants a grid that fills its box.

Also in here

The open tabs survive a reload. Refreshing put you back at the list with every terminal closed. The ids of the open tabs and the one in front are now remembered per account, and put back from the first session list the page receives — rebuilt from that list rather than from what was stored, so a restored tab is never a stale copy of a session, and one that has since ended does not come back. Nothing is written to the browser that the session list would not hand over anyway.

The board columns lose their box. Each column drew a border and a wash around cards that already carry both, so three short columns read as three mostly empty containers.

Checks

npm run typecheck, npx vitest run (20 files) and npm run build:web at the root; npm run typecheck, npm test (616 tests) and check:protocol in app/. The app's npm run build stops at check-bundle on this machine for want of Firebase values in .env.local, which is unrelated to the diff.