Add /graph G2: resumable budget, GraphUpdated status chip, PTY + turn-level coverage

BudgetLimited is now a resumable state: a budget trip demotes in-flight
nodes to Ready (a resource stop, not a verdict — no forever-Running node is
ever persisted) and '/graph resume --budget <tokens>' re-arms the graph with
fresh headroom (new budget = spent-so-far + extra). The tripped node's
partial burn is charged into tokens_spent_nodes at BOTH cascade sites before
the demotion clears current_node, so the top-up arithmetic never runs on an
under-counted ledger. Any input starting with 'resume' resolves to a resume
(case-insensitive; malformed top-ups surface the usage hint) and setup_graph
refuses to replace any non-Complete graph — a typo can no longer silently
destroy a resumable graph. An explicit --budget on a merely-paused graph is
rejected loudly instead of silently discarded; all trip-time messages now
advertise the top-up.

The pager gains a graph status chip: a new GraphUpdated wire variant
(extensions/notification.rs, old pagers degrade via #[serde(other)]) is
emitted from the single persist_graph_state chokepoint — every transition is
both a checkpoint and a badge tick — with a 'cleared' sentinel on /graph
clear and a one-shot re-emit after session restore (the replayed updates log
otherwise shows the pre-shutdown Active state that from_snapshot just
demoted in memory). TUI side: GraphDisplayState, session-notification arm,
and a goal-idiom chip with node progress, clamped current-node title, and
budget-aware spend. Pre-session command availability now advertises /graph
from the flags (it was fail-closed to the in-session path only, so the
welcome-screen slash menu never showed it).

Coverage: GraphUpdated wire round-trip + minimal-payload + unknown-tag
tests; PTY scenarios graph_slash_presession{,_disabled}.yaml (both run
green against the real pager binary); handle_prompt-level e2e for terminal
slash outcomes (/graph status|resume|pause, /goal refusals while the graph
owns the engine); budget top-up e2e driving a BudgetLimited diamond back to
Complete. Not shimmed: pre-G2 persisted snapshots with budget-Failed nodes
(the KIGI_GRAPH flag has never shipped enabled, so none exist).

kigi-shell 4927 and kigi-tui 6610 lib tests green; workspace clippy clean.

crates/codegen/kigi-tui/src/app/acp_handler/session_notification.rs

@@ -977,6 +977,37 @@ pub(super) fn handle_session_notification(notif: &acp::ExtNotification, app: &mu
         XaiSessionUpdate::InteractionResolved { tool_call_id } => {
             agent.dismiss_resolved_interaction(&tool_call_id)
         }
+        XaiSessionUpdate::GraphUpdated {
+            objective,
+            status,
+            total_nodes,
+            achieved_nodes,
+            failed_nodes,
+            running_nodes,
+            current_node_title,
+            token_budget,
+            tokens_spent,
+            pause_message,
+            ..
+        } => {
+            if status == "cleared" {
+                agent.graph_state.take();
+            } else {
+                agent.graph_state = Some(crate::app::agent::GraphDisplayState {
+                    objective,
+                    status: crate::app::agent::GoalDisplayStatus::parse(&status),
+                    total_nodes,
+                    achieved_nodes,
+                    failed_nodes,
+                    running_nodes,
+                    current_node_title,
+                    token_budget,
+                    tokens_spent,
+                    pause_message,
+                });
+            }
+            true
+        }
         _ => {
             tracing::trace!(
                 "Ignoring {}: {:?}",

crates/codegen/kigi-tui/src/app/agent.rs

@@ -385,6 +385,25 @@ impl GoalDisplayPhase {
         }
     }
 }
+/// Graph mode display state — the pager-side mirror of the
+/// `GraphUpdated` session notification (see the shell's
+/// `extensions/notification.rs`). Deliberately lean: the status chip
+/// shows counts + the current node; details live in `/graph status`.
+#[derive(Debug, Clone)]
+pub struct GraphDisplayState {
+    pub objective: String,
+    /// Reuses the goal display-status vocabulary (same wire strings).
+    pub status: GoalDisplayStatus,
+    pub total_nodes: u32,
+    pub achieved_nodes: u32,
+    pub failed_nodes: u32,
+    pub running_nodes: u32,
+    pub current_node_title: Option<String>,
+    pub token_budget: Option<i64>,
+    pub tokens_spent: i64,
+    pub pause_message: Option<String>,
+}
+
 /// Display state for an active goal, populated from `GoalUpdated`
 /// session notifications emitted by the goal orchestrator.
 #[derive(Debug, Clone)]

crates/codegen/kigi-tui/src/app/agent_view/mod.rs

@@ -745,6 +745,9 @@ pub struct AgentView {
     /// Current goal orchestration state. Set by `GoalUpdated` session
     /// notifications, cleared when a new session starts.
     pub goal_state: Option<super::agent::GoalDisplayState>,
+    /// Current graph orchestration state. Set by `GraphUpdated` session
+    /// notifications, cleared on the `"cleared"` sentinel / new session.
+    pub graph_state: Option<super::agent::GraphDisplayState>,
     /// The consumed parked-wait marker slot for the current turn, if any.
     /// Keyed by prompt id: a new turn naturally invalidates the slot with no
     /// explicit clear site. See [`ParkedMarkerSlot`].

crates/codegen/kigi-tui/src/app/agent_view/render.rs

@@ -1243,6 +1243,13 @@ impl AgentView {
                 ),
             );
         }
+        if let Some(ref graph) = self.graph_state {
+            let tick = self.tasks.tick_count() as usize;
+            status.push(
+                "graph",
+                crate::views::agent_status::graph_status_line(graph, &theme, tick),
+            );
+        }
         if let Some(mcp_line) = self.mcp_init_progress.as_ref().and_then(|p| {
             crate::views::agent_status::mcp_status_line(p, self.scrollback.animation_tick(), &theme)
         }) {

crates/codegen/kigi-tui/src/app/agent_view/session.rs

@@ -93,6 +93,7 @@ impl AgentView {
             chat_kind: false,
             app_chat_mode: false,
             goal_state: None,
+            graph_state: None,
             parked_wait_marker_for: None,
             end_work_announced: false,
             pending_stop_hooks: None,