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-shell/tests/common/mod.rs

@@ -0,0 +1,64 @@
+//! Shared helpers for kigi-shell integration tests.
+
+use kigi_shell::sampling::{ApiBackend, Client, SamplerConfig};
+
+/// Create a sampling client configured for a mock server. Shared by the
+/// integration tests so the ~30-field `SamplerConfig` literal lives in one
+/// place (`SamplerConfig` has no `Default`).
+pub fn create_test_client(base_url: &str, api_backend: ApiBackend) -> Client {
+    create_test_client_with_extra_headers(base_url, api_backend, &[])
+}
+
+/// Like [`create_test_client`] but seeds `SamplerConfig::extra_headers`, so a
+/// test can assert that session-injected headers reach the wire.
+pub fn create_test_client_with_extra_headers(
+    base_url: &str,
+    api_backend: ApiBackend,
+    extra_headers: &[(&str, &str)],
+) -> Client {
+    Client::new(test_sampler_config(base_url, api_backend, extra_headers)).unwrap()
+}
+
+/// The shared mock-server `SamplerConfig`; tests needing a non-default field
+/// (e.g. `doom_loop_recovery`) mutate the returned value before building the
+/// client themselves.
+pub fn test_sampler_config(
+    base_url: &str,
+    api_backend: ApiBackend,
+    extra_headers: &[(&str, &str)],
+) -> SamplerConfig {
+    // Shell `Client` is `kigi_sampler::SamplingClient`, which takes a
+    // `SamplerConfig` directly. Construct one inline here.
+    SamplerConfig {
+        api_key: Some("test-api-key".to_string()),
+        base_url: base_url.to_string(),
+        model: "test-model".to_string(),
+        max_completion_tokens: Some(1000),
+        temperature: Some(0.7),
+        top_p: None,
+        api_backend,
+        auth_scheme: Default::default(),
+        extra_headers: extra_headers
+            .iter()
+            .map(|(k, v)| (k.to_string(), v.to_string()))
+            .collect(),
+        context_window: 256_000,
+        client_version: None,
+        force_http1: false,
+        max_retries: None,
+        stream_tool_calls: false,
+        idle_timeout_secs: None,
+        client_identifier: None,
+        reasoning_effort: None,
+        deployment_id: None,
+        user_id: None,
+        origin_client: None,
+        attribution_callback: None,
+        bearer_resolver: None,
+        supports_backend_search: false,
+        compactions_remaining: None,
+        compaction_at_tokens: None,
+        doom_loop_recovery: None,
+        header_injector: None,
+    }
+}