M0: compilable skeleton — Kigi 0.1.0 fork surgery

Hard fork of xai-org/grok-build (Apache-2.0) re-targeted as Kigi, an
unofficial Kimi Code CLI community build.

Rename & identity
- 72 xai-*/xai-grok-* crates -> kigi-* (explicit: xai-grok-pager-bin ->
  kigi-bin [binary `kigi`], xai-grok-pager -> kigi-tui; rest mechanical);
  ptyctl, ptyctl-cli, third_party/ unchanged; proto package
  xai.grok.tools.v1 -> kigi.tools.v1
- Config home ~/.kigi (KIGI_SHARE_DIR override), env prefix GROK_* ->
  KIGI_*, `kigi --version` carries the unofficial-community-build notice
- clap identity, help text, startup banner, prompt templates rebranded
  (templates re-encrypted)

Deletions (PRD removal list #5/#6/#7/#9/#10)
- voice input (xai-grok-voice) and all TUI wiring
- telemetry: Mixpanel client, external OTel stream, Sentry, OTLP layers,
  trace/GCS/S3 upload queues (kigi-file-utils halved), workspace upload
  module & dc_log, heap-profile uploader, auth-diagnostics uploader,
  session-analytics halves of feedback; local zero-egress observability
  preserved in new kigi-log crate (unified log, --debug firehose,
  subsystem file logs, opt-in instrumentation)
- announcements (crate, remote-settings fields, TUI surfaces)
- plugin marketplace (crate, sources/browse/CTA/extensions-modal tab);
  direct plugin install/uninstall/update via kigi-agent git_install kept
- relay/gateway/assets endpoints and features (agent relay, headless
  relay transport, gateway bridge, LeaderEnvUrls); leader IPC socket now
  ~/.kigi/leader.sock + KIGI_LEADER_SOCKET, no ws-url derivation
- functional types rehomed instead of deleted: PermissionMode ->
  kigi-config-types, McpInitStrategy -> kigi-mcp, PrCreationSource ->
  session signals, TerminalDiagnostics -> kigi-pager-render, agent_id ->
  shell util

Endpoints
- kigi-env rewritten: single production KigiEndpoints {coding_api_base_url
  https://api.kimi.com/coding/v1 (KIGI_CODE_BASE_URL), oauth_host
  https://auth.kimi.com (KIGI_OAUTH_HOST), update_base_url (GitHub
  Releases API), upgrade_page_url}; GrokBuildEnvironment enum deleted

Toolchain & workspace hygiene
- Rust 1.97.0 pinned; edition 2024; full cargo update; git2 hoisted to
  workspace at 0.21 (Option->Result API migration), quick-xml 0.41
- Root Cargo.toml hand-maintained (PRD §8.1): version 0.1.0 inherited by
  all members, members sorted, unused deps pruned
- cargo-deny advisories gate (deny.toml with documented transitive
  exceptions); CI workflow (check/clippy/fmt/deny/test, macOS+Linux)
- cross-crate test seams re-gated behind `test-support` cargo feature;
  insta snapshot baselines renamed to the kigi_tui prefix
- clippy --workspace --all-targets: zero warnings; fmt clean

Fixes surfaced by the port
- updater probe/installer divergence (bin/kigi vs bin/grok symlink set)
- idle model-metadata refresh dead under KIGI_CODE_BASE_URL override
  (new is_effective_coding_endpoint_url, loopback+override aware)
- macOS symlinked-TMPDIR fixture canonicalization (foreign_sessions,
  fast-worktree); RSS measurement tests serialized via serial_test

Docs & legal (Apache §4)
- NOTICE added (upstream attribution + change statement); THIRD-PARTY
  notices sustained; kigi-tools ported-code notices extended; README,
  CONTRIBUTING, SECURITY, AGENTS.md rewritten

Out of scope for M0 (tracked): Kimi auth/inference (M1), search/fetch,
command parity, config import (M2), Computer Hub excision & final
brand-token sweep (M2), distribution & self-update rewrite (M3).

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

@@ -0,0 +1,103 @@
+use super::*;
+
+/// Update the activity label on a subagent's collapsed scrollback block.
+///
+/// Skips the write (and cache invalidation) when the label hasn't changed,
+/// so the per-delta common case ("Responding" stays "Responding") allocates
+/// nothing.
+pub(super) fn sync_activity_label(
+    scrollback: &mut crate::scrollback::state::ScrollbackState,
+    entry_id: Option<crate::scrollback::entry::EntryId>,
+    activity_label: Option<&str>,
+) {
+    if let Some(eid) = entry_id
+        && let Some(entry) = scrollback.get_by_id_mut(eid)
+        && let RenderBlock::Subagent(ref mut sb) = entry.block
+        && sb.activity_label.as_deref() != activity_label
+    {
+        sb.activity_label = activity_label.map(str::to_owned);
+        entry.invalidate_cache();
+    }
+}
+
+/// Fan a subagent's computed activity label out to both surfaces that show
+/// it — the collapsed scrollback block and the [`SubagentInfo`] backing the
+/// tasks pane / dashboard rows — so the two can't drift.
+pub(super) fn sync_subagent_activity(
+    parent: &mut AgentView,
+    child_key: &str,
+    activity_label: Option<String>,
+) {
+    let Some(info) = parent.subagent_sessions.get_mut(child_key) else {
+        return;
+    };
+    sync_activity_label(
+        &mut parent.scrollback,
+        info.scrollback_entry_id,
+        activity_label.as_deref(),
+    );
+    info.activity_label = activity_label;
+}
+
+/// Resolve a subagent child view's live activity into the display label the
+/// fan-out stamps ("Waiting" while the child is busy between activities).
+pub(super) fn subagent_activity_label(child_view: &AgentView) -> Option<String> {
+    match child_view.resolve_turn_activity() {
+        Some(a) => Some(crate::app::subagent::format_activity_label(&a)),
+        None if child_view.session.state.is_busy() => Some("Waiting".to_string()),
+        None => None,
+    }
+}
+
+/// Synthesize a finish for a stuck row when a kill found nothing live to stop
+/// (else `pending_kill` times out → "running"). `status` is the real terminal
+/// status for an already-finished orphan, else `"cancelled"`.
+pub(crate) fn finalize_killed_subagent(
+    app: &mut AppView,
+    session_id: &acp::SessionId,
+    subagent_id: &str,
+    status: &str,
+) -> bool {
+    let Some(SessionMatch::Root(agent_id)) = find_session_match(app, session_id) else {
+        return false;
+    };
+    let Some(agent) = app.agents.get(&agent_id) else {
+        return false;
+    };
+    // Idempotency: skip if already finished.
+    let Some(child_session_id) = agent
+        .subagent_sessions
+        .values()
+        .find(|i| i.subagent_id.as_ref() == subagent_id && !i.finished)
+        .map(|i| i.child_session_id.to_string())
+    else {
+        return false;
+    };
+
+    let payload = SessionNotification {
+        session_id: session_id.clone(),
+        update: XaiSessionUpdate::SubagentFinished {
+            subagent_id: subagent_id.to_string(),
+            child_session_id,
+            // An already-finished orphan may be "failed", but the cancel response
+            // carries no failure reason (lost across the resume window), so
+            // `error` stays None.
+            status: status.to_string(),
+            error: None,
+            tool_calls: 0,
+            turns: 0,
+            // Real run time is unknown for an already-gone orphan (the row's
+            // started_at is stamped at resume, not the real spawn), so emit 0.
+            duration_ms: 0,
+            tokens_used: 0,
+            output: None,
+            will_wake: false,
+        },
+        meta: None,
+    };
+    let Ok(params) = serde_json::value::to_raw_value(&payload) else {
+        return false;
+    };
+    let notif = acp::ExtNotification::new("x.ai/session/update", params.into());
+    handle_ext_notification(&notif, app)
+}