AgentHUD

Added

• opencode provider (read-only SQLite). opencode keeps all sessions in
  a single SQLite database rather than per-session files, so the provider
  opens it read-only via Node's built-in node:sqlite and surfaces
  sessions, sub-agents (via parent_id), model, context gauge, liveness,
  and the activity timeline. Loaded through a guarded require so agenthud
  still runs on Node < 22 (the provider is simply unavailable there — no
  new dependency, no engine bump). Schema: docs/schemas/opencode-session.md.
• Sticky live projects. In a short Projects panel, projects that are
  running right now stay anchored as a sticky block at the top — header
  plus their sessions/sub-agents, hierarchy intact — so the live monitor
  never scrolls active work out of view; only the cold tail scrolls. A
  project is "live" when it has a working/waiting session or a working
  sub-agent (keyed on liveState, not the 30-min hot window, so a project
  whose sub-agents just finished doesn't stay pinned). Live projects sort
  first; the prefix is capped so it can't swallow the whole panel.

Fixed

• Row border alignment. The ... N more (Projects) and No activity yet (viewer) lines were one cell narrower than every other row — their
  right border sat one column to the left. Dropped a stray -1 in the
  padding.
• Bound widthCache to stop unbounded memory growth. getDisplayWidth
  memoized string-width results in a never-evicted map; per-render
  dynamic strings (elapsed time, context %, timestamps) accumulated
  forever. Capped with FIFO eviction (~0.5 MB ceiling), preserving the
  CPU win for the genuinely-recurring strings.

Changed

• Session ID display. Sub-agents truncate their (no-longer-short)
  agentId to 6 chars instead of printing it verbatim; parent sessions
  keep their 4-char short ID. opencode's time-ordered ses_… ids show
  their distinguishing random tail rather than the shared timestamp prefix.