AgentHUD

Changed (BREAKING)

• Hide moved from h to Shift+H. Lowercase h is now the
  vim-left alias for ← (jump to parent). The old binding
  (h = hide) was a footgun: vim users coming for navigation
  hit h and silently hid whichever item was selected. The
  user wouldn't even remember pressing it. Capital H keeps the
  mutation behind a deliberate keystroke.

Added

• Tree-wide census in the Projects panel title. Each level
  shows total + visible-active count:
  12p (3) · 68 sessions (5) · 142 sub-agents (2) · ⊘ 14 hidden (1).
  The (N) parentheticals are green so the eye lands on the
  actionable count. The hidden (M) is yellow — the alert for
  content you can't see. Narrow terminals fall back to short
  form (68s (5), 142a (2)), then drop segments from the
  right; the hidden alert is the last thing to go.
• a key toggles "show hidden items" in the tree. Hidden
  projects and sessions render dim with a ⊘ marker so they're
  recognizable at a glance. Combined with the H change below,
  a full hide → toggle → unhide cycle now lives inside the TUI —
  no more state.yaml editing to recover an accidentally-hidden
  item.
• H is now a toggle, not just hide. Pressing H on a
  visible item hides it (same as before); pressing it on a
  hidden item unhides it. Combine with a to reveal hidden
  items in the tree, navigate to the one you want, and toggle
  with H.
• Per-project session + sub-agent counts on the project row.
  > myproj ~/path 5 sessions (2) · 142 sub-agents (3) 3m.
  Totals are dim; active subset (N) is mid-tone green
  (non-bold, softer than the panel-title census so it doesn't
  compete with the row's own [hot]/[warm] badge). Width-
  aware: short form 5s (2) · 142a (3), dropped entirely on
  very narrow terminals.
• Status bar surfaces hidden-but-still-active items. A hidden
  session producing live activity used to be completely
  invisible — combined with the h footgun above, that broke
  discovery in a way that took a state.yaml edit to recover.
  Now the title bar shows the count: · ⊘ N hidden (dim) or
  · ⊘ M active in N hidden (yellow M) when something hot
  or warm is hidden.
• Cold sessions under active projects collapse to a
  ... N cold sentinel. Active projects often hold a long
  tail of historical cold sessions that bury the live work;
  pressing ↵ on the sentinel reveals them.

Changed (layout)

• Census moved to the Projects panel title bar; branding +
  keybindings moved to a single bottom row. The top status
  bar was wasted space (just "AgentHUD vX · ⊘ N hidden …"
  floating above the panels) and the Projects title was equally
  wasted (just "Projects"). Both fixed: census now sits where
  it belongs — directly above the tree it describes — and the
  bottom row carries the brand + keys.
• Session row description = latest substantial user request.
  Was: first natural-language user prompt (often stale by hour
  3 of a long session). Now: the most recent user message that
  is ≥ 10 chars and doesn't start with / (so trivial
  follow-ups like "ok", "go", "yes" and slash commands like
  /compact, /clear are skipped). Falls back to first prompt
  when no later message qualifies.
• t (toggle tracking) now requires tree focus. It moves
  the tree cursor — accidentally pressing it while reading the
  viewer used to yank focus away. The TRK ● indicator still
  appears on both tree and viewer banners while the mode is on.
• t: track and r: refresh hints dropped from the status
  bar. Tracking is a niche mode; refresh is automatic via the
  2s poll + fs.watch. Both keys still work and are documented
  in the ? help.

Fixed

• Hidden sub-agents are now MARKED, not filtered, in the data
  layer. Previously hidden sub-agents were silently dropped
  before the tree was built, so the panel-title census
  undercounted sub-agent totals, the yellow hidden-active alarm
  was silent for them, and the a (show hidden) + H (unhide)
  round-trip couldn't reach them at all. Now they ride along
  with hidden: true and the show-hidden/unhide flow works
  end-to-end.
• H no longer teleports selection when showHidden is on.
  In show-hidden mode the row stays rendered (dimmed with ⊘)
  after hiding, so jumping selection away made no sense — the
  user just acted on that row and expects to remain on it. Now
  selection only advances when the row is about to disappear
  (showHidden off).
• Cold session rows render dim instead of bold-bright. The
  cold IDs used to compete visually with the active rows in the
  same project.