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-pager-pty-harness/src/scenarios/scroll_stress.rs

@@ -0,0 +1,65 @@
+//! `scroll_stress` — inject rapid `j` keys against a large pre-rendered
+//! response, measure frame timing.
+//!
+//! What it stresses: `render_scrolled_entries_with_scratch`, partial-entry
+//! clipping (ScratchBuffer cell copy), `Buffer::diff()`.
+
+use std::time::{Duration, Instant};
+
+use anyhow::Result;
+
+use super::{BenchResults, ContentController, PtyHarness, wait_for_welcome};
+use crate::keys;
+
+const LINES: usize = 500;
+const SCROLL_KEYS: usize = 200;
+const KEY_INTERVAL: Duration = Duration::from_millis(16);
+
+pub async fn run(harness: &mut PtyHarness, content: &ContentController) -> Result<BenchResults> {
+    // 1. Prime the mock server with a large markdown response.
+    content.set_response(long_markdown_response(LINES));
+
+    // 2. Wait for the pager's splash screen.
+    wait_for_welcome(harness).await?;
+
+    // 3. Submit a prompt so the mock inference server returns the big response.
+    //    The pager is interactive: type a short prompt then hit Enter.
+    harness.inject_keys(b"go\r")?;
+
+    // 4. Wait until the streamed response is on screen.
+    //    The response is `Lorem ipsum dolor ...` — look for a word we know
+    //    will appear after streaming starts.
+    harness.wait_for_text("Lorem", Duration::from_secs(30))?;
+
+    // 5. Let the full response settle, then reset timing to start clean.
+    harness.update(Duration::from_millis(500));
+    harness.reset_timing();
+
+    // 6. Inject scroll-down keys at a fixed interval while collecting frames.
+    let wall_start = Instant::now();
+    for _ in 0..SCROLL_KEYS {
+        harness.inject_keys(keys::J)?;
+        harness.update(KEY_INTERVAL);
+        if !harness.is_running() {
+            break;
+        }
+    }
+    // Drain any straggler frames.
+    harness.update(Duration::from_millis(250));
+    let wall_time = wall_start.elapsed();
+
+    Ok(harness.bench_results("scroll_stress", wall_time))
+}
+
+/// Generate `n` lines of predictable markdown. Used both as scenario
+/// payload and as a basic smoke test of the wrapping pipeline.
+fn long_markdown_response(n: usize) -> String {
+    let mut out = String::with_capacity(n * 80);
+    out.push_str("# Scroll stress response\n\n");
+    for i in 0..n {
+        out.push_str(&format!(
+            "Line {i}: Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.\n"
+        ));
+    }
+    out
+}