v0.1.92 — TUI tool filters, session preview/sort, workspace drawer, accessibility modes

Second TUI batch — tool-inspector filters + navigation, session browser preview/sort, workspace drawer, and accessibility modes:

• /tools filters — f cycles All → Failures → Writes → Running, keeping keyboard selection within the filtered list. PgUp/PgDn move five calls, Home/End jump to the first/last in the active filter, and g closes the inspector and jumps the transcript to the selected call's activity line.
• Session browser preview/sort — p shows the selected session's metadata (title, message count, updated time); s toggles recent-first / title order.
• Persistent workspace drawer — on terminals ≥ 96 columns wide, a compact row below the header keeps workspace, branch, tool count, undo availability, and queued-work state visible during active turns.
• Accessibility modes — ui.accessibility: high-contrast (black background, high-contrast semantic colors) and ascii (emoji → ASCII labels for terminals without emoji fonts), applied live via /settings and /set; NO_COLOR suppresses color styling.
• Fix: the session browser's s/p keys were unreachable (they landed in the settings key handler by mistake) — moved to the sessions handler, with an early return so the preview text isn't cleared. Covered by TestSessionsSortAndPreview.

Unit tests + go test -race clean; ASCII mode live-smoke-tested ([C]/[T] icons render, modals don't crash).