New config to show skills+plugins in the tokens/cost row

[tmck-code]

Context

Headline change: the trailing column of the tokens/cost row now shows skills + plugins instead of the tokens-over-time sparkline. The sparkline isn't gone — it moves to its own optional full-width row, off by default:

• [layout].show_tokens_over_time = true / YAS_SHOW_TOKENS_OVER_TIME=true — adds a "tokens over time" row (t/m rate + live sparkline) under the tokens/cost band. Documented in the README config table and yas.example.toml.

Alongside that, fixes three related rendering bugs surfacing across width/config combinations users actually hit:

1. The skills + plugins trailing column vanished entirely (instead of rendering as an empty bordered section) when there were no skills/plugins loaded, which dragged the borders and labels for the neighboring loc r/w and cost sess/day sections along with it.
2. The loc r/w and cost sess/day labels silently disappeared from the border row when show_icons=False, because label detection sniffed for an icon glyph that's gated on show_icons instead of using an explicit flag.
3. The loc r/w label wasn't centered within its section — it centered against the long label form's width instead of the abbreviated form actually rendered.

No version bump on this branch (rebased onto main at 0.9.0).

Changes

Renderer / layout

• claude/yas/layout.py — skills + plugins always occupy the trailing tokens/cost column; new opt-in tokens over time row below it. Consumes has_lines directly for the loc r/w label anchor; centers the loc r/w label using the abbreviated label form's width (matching what _fit_label actually renders) instead of the long form's width.
• claude/yas/renderer.py — tokens_cost no longer gates the skills+plugins trailing column on non-empty content; it now always renders (blank-padded) when width allows. Also returns an explicit has_lines flag instead of forcing callers to re-derive presence from rendered glyphs.
• claude/yas/render/text.py, claude/yas/config.py, claude/yas/constants.py — show_tokens_over_time config option and the new row's rendering + label constants.

Docs

• README.md, yas.example.toml — document show_tokens_over_time.

Follow-ups from review

• An overlong skills+plugins list is now truncated with … to the real free column width (gate on PLUGINS_TRAILING_MIN_W) instead of being pre-clipped at 60 cols or shed entirely; new clip_visible() helper in render/text.py; leader_* → trailing_* renames.

Tests

• Updated test_tokens_cost.py, test_layout_seam.py, test_labels_layout.py, test_tool_counts_row.py, test_config.py for the new column/border layout.
• Added test/test_tokens_over_time.py for the new row.
• Regenerated test/fixtures/claude_dark_wide.ansi snapshot to match the corrected renderer output.

Checklist

• Tests added or updated for new/changed behaviour
• (bug fixes) a regression test now covers the situation so it can't come back

Screenshots / recording

	before / after
kitchen-sink
no-icons
tokens-over-time
long-skills-plugins-185

Benchmark

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
main	45.6 ± 3.2	42.6	65.5	1.01 ± 0.08
PR	45.2 ± 1.3	42.4	48.7	1.00

System info

Key	Value
OS	Linux archlinux 7.1.8-arch1-3 #1 SMP PREEMPT_DYNAMIC Tue, 11 Aug 2026 09:16:08 +0000 x86_64 GNU/Linux
Claude Code	2.1.235 (Claude Code)
Terminal	TERM=tmux-256color TERM_PROGRAM=tmux SHELL=/bin/bash COLORTERM=truecolor
Locale	LANG=en_AU.UTF-8 LC_ALL=
Python	Python 3.13.13
uv	uv 0.12.3 (507230998 2026-08-07 x86_64-unknown-linux-gnu)