Fit the table in 80 columns, badge errors, coarsen the countdown

[callicles]

Fixes #33.

Three TUI design improvements from @forthrin's feedback (continuing the #25 thread), plus a re-recorded demo GIF.

1. Errors as a white-on-red badge

theme.error grew from a single Color to a theme::Paint { fg, bg: Option }, written "<fg> on <bg>" in the config (spaced separator, so ratatui's two-word aliases like bright red still parse). The default is white on lightred — the reporter's \033[101m.

Only the failure markers take the background: the row's verdict glyph, the status word, and the "not a domain name" label. Everything else that uses the error role — map dots, gauge fill, legend swatch, footer counters, slow-ping times, and all error prose — renders the role's hue as a plain foreground. A background behind a 42-character error sentence turns the row into a red bar, and the error role doubles as the slow-latency color, so badging it everywhere would paint the Ping column red. A plain color in the config (error = "lightred") still works and simply drops the badge.

2. The table fits 80 columns

Column widths now come from app::TableLayout::fit(width, resolvers) — computed in app.rs where it's testable, not left to ratatui's constraint solver, because which column gives way first is a judgement call worth pinning down. Sheds cheapest-first: spelled-out status word → an IPv6 resolver's full address → the resolver name. Never shed: the numeric columns, the 15 columns a full IPv4 needs, and a 16-column answer.

At 80 columns this lands exactly (mark 1 + name 17 + loc 8 + ip 15 + ping 5 + ttl 6 + exp 3 + answer 16 + 7 gaps + 2 borders = 80). The verdict glyph (✓ ≠ ! ↻ ∅ ✗) moves to the left margin so failures scan down one edge; when the status word is shed the glyph still carries the verdict. Ping/TTL/Exp are right-aligned (headers too) and the per-row units are dropped — the header names them.

IPv6 resolver addresses: the IP column sizes to the widest address in the list, clamped to [15, 39] — shown whole on a wide terminal, clipped to IPv4 width at 80 columns (cropping one rare address beats cropping the columns the issue asked to fit).

No wide regression: TableLayout::reserved_width() reproduces the old 103-column reservation exactly, so the globe still appears at ≥131 and the flat map at ≥157, and the answer column is unchanged next to a map panel.

--once output matches the TUI's name/loc/ip widths and right-aligns the TTL; it keeps status words and units since it's a headerless, grep-able plain format.

3. Coarse countdown

app::fmt_countdown: at most two digits and a unit — 59s → 1m → 59m → 1h → 23h → 1d, saturating at 99d. Truncating, not rounding, so 1m means at least a minute remains. Applied only to the per-row Exp column (the one that ticked out of unison); the TTL advisory notes, the outlier attribution, and the gauge's "old answers expire in ≤" keep the precise fmt_secs format — those are single figures where precision is the point. Expired rows show 0s (fits the 3-cell column; "expired" didn't).

Verification

Quality gates (what CI runs):

cargo fmt --check                         → clean
cargo clippy --all-targets -- -D warnings → clean
cargo test                                → 120 passed; 0 failed

New tests: the full countdown ladder from the issue plus boundaries (59s→1m, 59m→1h, 23h→1d, >99d, u64::MAX, width ≤3 always); the 80-column layout summing to exactly 80 with untouched numerics; wide layouts spending extra width only on the answer; IPv6 wide-vs-narrow behavior; Paint parsing with/without background and badge-vs-tint semantics; config theme.error = "black on yellow" round-trip and error-key attribution.

PTY verification (expect + pyte, per the AGENTS.md gotchas):

• 80×24: ✓ Google Public DNS →YUL 8.8.8.8 29 246 3m 104.20.23.154, 1… — full IPs (208.67.222.222, 149.112.121.10 intact), right-aligned numerics, coarse Exp (39s, 1m, 4m), status word shed, answer visible.
• 160×24: status word back, full answers, globe panel present — wide layout unchanged.
• ERR rows (TEST-NET resolver 192.0.2.1 via DNSGLOBE_CONFIG): the ✗ cell reads back fg=ffffff bg=ff0000 bold from the terminal emulator, while the timeout message carries no background — the badge stays on the marker only. Same verified for ∅ NONE rows and the "not a domain name" gauge badge.
• cargo run -- example.com --once and 514.ax --once TXT confirm the plain-text output.

Demo GIF re-recorded with vhs from demo/demo.tape (2.4 MB, was 2.6 MB).

Known pre-existing limitation (out of scope): the gauge and footer hint lines still run past 80 columns and clip — they're un-wrapped Paragraphs and the key-hint line can't fit 80 regardless; worth its own follow-up if it matters.

🤖 Generated with Claude Code