fix(tui): compact detailed sidebar metrics

[Sayt-0]

Summary

• adapt Detailed sidebar metrics to the width required by the current agent roster
• use compact Eff, Ctx, and Cost forms without the decorative effort gauge at constrained and default widths
• preserve semantic effort values, agent names, and model rows while packing metrics onto the fewest lines that fit
• restore full labels and gauges when every agent's complete metric row fits

Fixes #3856

Before and after

Width	Before	After
Default sidebar	Effort ▰▰▰▰▱▱ high Context 30% · Cost $0.13	Eff high · Ctx 30% · Cost $0.13
Minimum sidebar	Effort ▱▱▱▱▱▱ off Ctx 6% Cost $0.0042	Eff off · Ctx 6% Cost $0.0042
Sufficiently wide	Full labels and gauge	Full labels and gauge, unchanged

The existing issue screenshot captures the visual before state. The table above shows the exact ANSI-stripped rendering pinned by the updated tests; no replacement screenshot is included because the result depends on the active roster and terminal width.

Issue expectations

Expectation	Implementation
Keep Detailed mode at narrow/default widths	The renderer stays in Detailed mode and changes only its metric vocabulary and flow
Use compact atomic labels	Constrained cards render Eff, Ctx, and Cost
Remove cramped gauge/value combinations	Compact effort rows omit the six-cell gauge and retain values such as high, off, minimal, auto, and token budgets
Keep names and models readable	Name and provider/model rows remain separate and preserve existing truncation behavior
Reduce vertical space	Compact metrics flow greedily; default-width cards use one joined metric row when it fits
Handle the width boundary	The roster switches to full labels and gauges only when every full joined metric row fits
Update correctly on resize	Tests cover default -> wide threshold -> default and verify exact restoration, line widths, and card ownership

Validation

• task lint
• task build
• env -u HTTP_PROXY -u HTTPS_PROXY -u ALL_PROXY -u http_proxy -u https_proxy -u all_proxy task test
• go test ./pkg/tui/components/sidebar ./pkg/tui/page/chat -count=1 -race
• git diff --check

The full test suite requires the workspace HTTP proxy variables to be unset because the injected localhost proxy intentionally intercepts private-address requests used by SSRF tests.