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-tools/src/attribution.rs

@@ -0,0 +1,103 @@
+//! 401 attribution: callback hook + shared helpers for tool HTTP clients.
+
+use std::sync::Arc;
+
+/// Bearer prefix length shared across crate boundaries.
+pub const SENT_BEARER_PREFIX_LEN: usize = 12;
+
+/// Which tool endpoint produced the 401.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum ToolConsumer {
+    ImageGen,
+    VideoGenStart,
+    VideoGenPoll,
+    WebSearch,
+}
+
+impl ToolConsumer {
+    pub fn as_str(self) -> &'static str {
+        match self {
+            Self::ImageGen => "ImageGen",
+            Self::VideoGenStart => "VideoGen.start",
+            Self::VideoGenPoll => "VideoGen.poll",
+            Self::WebSearch => "WebSearch",
+        }
+    }
+}
+
+/// 401 attribution callback. Shell wires this to emit telemetry.
+pub trait Auth401AttributionCallback: Send + Sync + std::fmt::Debug {
+    /// `sent_bearer_prefix` is truncated to [`SENT_BEARER_PREFIX_LEN`]
+    /// before crossing this boundary. `None` = no bearer was sent.
+    fn record_401(&self, consumer: ToolConsumer, sent_bearer_prefix: Option<&str>);
+}
+
+/// Shared, cheap-to-clone alias for the attribution callback.
+pub type SharedAttributionCallback = Arc<dyn Auth401AttributionCallback>;
+
+/// Record a 401 attribution event if a callback is wired. Truncates
+/// the bearer to [`SENT_BEARER_PREFIX_LEN`] before crossing the
+/// trait boundary.
+pub(crate) fn emit_401(
+    callback: Option<&SharedAttributionCallback>,
+    consumer: ToolConsumer,
+    sent_bearer: Option<&str>,
+) {
+    if let Some(cb) = callback {
+        let prefix = sent_bearer.map(|s| truncate_to_prefix(s.to_string()));
+        cb.record_401(consumer, prefix.as_deref());
+    }
+}
+
+/// Truncate a bearer string to the first [`SENT_BEARER_PREFIX_LEN`]
+/// characters. Used by tool clients before passing the bearer across
+/// the [`Auth401AttributionCallback`] boundary.
+///
+/// Bearer tokens are ASCII (per the `Authorization` header grammar)
+/// so the byte index is always a char boundary; this function uses
+/// `String::truncate` which would otherwise panic on a non-boundary
+/// cut.
+pub(crate) fn truncate_to_prefix(mut bearer: String) -> String {
+    bearer.truncate(SENT_BEARER_PREFIX_LEN.min(bearer.len()));
+    bearer
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn truncate_to_prefix_long_string_cuts_at_12() {
+        assert_eq!(
+            truncate_to_prefix("xai-key-aaaaaaaaaaaaaaaaaaa".to_string()),
+            "xai-key-aaaa"
+        );
+    }
+
+    #[test]
+    fn truncate_to_prefix_short_string_unchanged() {
+        assert_eq!(truncate_to_prefix("abc".to_string()), "abc");
+    }
+
+    #[test]
+    fn truncate_to_prefix_exact_12_unchanged() {
+        assert_eq!(
+            truncate_to_prefix("123456789012".to_string()),
+            "123456789012"
+        );
+        assert_eq!(truncate_to_prefix("123456789012".to_string()).len(), 12);
+    }
+
+    #[test]
+    fn truncate_to_prefix_empty_unchanged() {
+        assert_eq!(truncate_to_prefix(String::new()), "");
+    }
+
+    #[test]
+    fn tool_consumer_as_str_stable_identifiers() {
+        assert_eq!(ToolConsumer::ImageGen.as_str(), "ImageGen");
+        assert_eq!(ToolConsumer::VideoGenStart.as_str(), "VideoGen.start");
+        assert_eq!(ToolConsumer::VideoGenPoll.as_str(), "VideoGen.poll");
+        assert_eq!(ToolConsumer::WebSearch.as_str(), "WebSearch");
+    }
+}