Rebuild grid agent TUI with Ratatui dashboards

docs/grid-agent-tui.md

@@ -1,8 +1,9 @@
 # Grid-agent operator TUI
 
-The operator TUI is a pure-Rust, cross-platform view of the versioned control
-plane. Embedded and split modes use the same reducer, snapshots, commands, and
-authenticated control requests; the UI never reads private runtime state.
+The operator TUI is a pure-Rust, cross-platform Ratatui dashboard over the
+versioned control plane. Embedded and split modes use the same reducer,
+snapshots, widgets, commands, and authenticated control requests; the UI never
+reads private runtime state. Standalone preferences uses the same Ratatui form.
 
 Run an embedded UI with a live-grid integrated configuration:
 
@@ -31,19 +32,33 @@ Up/Down to select, Enter to edit/commit, `w` to save, and Esc to cancel. Changes
 to connection or authorization settings apply after restart. A one-time
 `--import-env /path/to/.env` migrates legacy `GRID_*` and `OPENAPI_*` values.
 
-Use Tab/arrow keys to change panels and scroll. `r` refreshes; `p`/`u` pause or
-resume; `f` reconnects the grid; `a`/`d` approve or deny the first pending
-approval; `x` cancels the newest visible action; `e` expires the first visible
-session; `t` toggles the first roaming schedule; `s` requests shutdown; and
-`q` or Ctrl-C exits. Mutations other than pause/resume require confirmation,
-with shutdown marked high risk. Exiting or crashing a split TUI does not stop
-the service.
+The Overview dashboard shows readiness, region/pose, behavior, build and visual
+work, approvals, and recent failures. Queues & budgets shows real queue and
+rate-limit gauges, active work, outcome counts, dropped events, aggregate
+latency, and a bounded 120-refresh history. Sessions, roaming schedules,
+approvals, timeline/audit, errors, diagnostics, health, and preferences retain
+focused tables or panels and contextual detail. Missing backend data is marked
+unavailable rather than estimated.
 
-Rendering is terminal-independent, Unicode display-width aware, responsive to
-resize events, and monochrome when `NO_COLOR` is set or `TERM=dumb`. Input uses
-a bounded queue. Snapshot ticks coalesce while a request is slow, and timeline
-storage is bounded. The terminal guard restores raw mode, cursor visibility,
-and the alternate screen on success, error, Ctrl-C, or panic unwinding.
+Use Tab/Shift-Tab or Left/Right to change panels and Up/Down to select rows.
+`/` searches event, audit, correlation, time, duration, result, and reason data;
+Enter applies the search and Esc clears it. `r` refreshes; `p`/`u` pause or
+resume; `f` reconnects the grid; `a`/`d` approve or deny the selected approval;
+`x` cancels the newest visible action; `e` expires the selected session; `t`
+toggles the selected roaming schedule; `s` requests shutdown; and `q` or
+Ctrl-C exits. Mutations other than pause/resume require confirmation, with
+shutdown marked high risk. Exiting or crashing a split TUI does not stop the
+service.
+
+Ratatui's Crossterm backend provides buffered/diff rendering without clearing
+the full screen on every frame. Layouts respond to resize and collapse to a
+compact status view on very small terminals; focus and failure markers remain
+visible without color when `NO_COLOR` is set or `TERM=dumb`. Input, refresh
+work, results, event history, errors, and performance history are all bounded.
+Slow snapshots run outside the input reducer, and refresh ticks are dropped
+when the bounded worker queue is full. The terminal guard restores raw mode,
+cursor visibility, and the alternate screen on success, error, Ctrl-C, or
+panic unwinding.
 
 Diagnostic panels show only explicitly captured redacted envelopes. Prompt
 and response content, API keys, grid passwords, operator tokens, capability
@@ -52,7 +67,8 @@ URLs, and model reasoning have no TUI representation.
 Focused verification:
 
 ```sh
-cargo test --locked -p metacrate-grid-agent --lib tui_tests
+cargo test --locked -p metacrate-grid-agent tui --lib
+cargo test --locked -p metacrate-grid-agent --test preferences_config
 cargo test --locked -p metacrate-grid-agent --test dependency_policy
 cargo clippy --locked -p metacrate-grid-agent --all-targets --features live-grid -- -D warnings
 RUSTDOCFLAGS="-D warnings" cargo doc --locked -p metacrate-grid-agent --no-deps