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/common/kigi-computer-hub-mcp-adapter/src/metrics.rs

@@ -0,0 +1,61 @@
+//! Feature-gated Prometheus metrics for the MCP adapter bridge.
+//!
+//! When the `metrics` cargo feature is enabled, each helper records to a
+//! lazily-registered Prometheus counter / gauge / histogram. When
+//! disabled (the default), every helper compiles to an empty function
+//! body so the crate carries zero prometheus dependency.
+
+#[cfg(feature = "metrics")]
+mod inner {
+    use prometheus::{
+        Histogram, IntCounter, IntGauge, exponential_buckets, register_histogram,
+        register_int_counter, register_int_gauge,
+    };
+    use std::sync::LazyLock;
+
+    static MCP_CALL_DURATION_SECONDS: LazyLock<Histogram> = LazyLock::new(|| {
+        register_histogram!(
+            "computer_hub_mcp_call_duration_seconds",
+            "MCP server response latency for tool calls.",
+            exponential_buckets(0.01, 2.0, 14).expect("valid bucket params")
+        )
+        .expect("computer_hub_mcp_call_duration_seconds must register once")
+    });
+
+    static MCP_ERRORS_TOTAL: LazyLock<IntCounter> = LazyLock::new(|| {
+        register_int_counter!(
+            "computer_hub_mcp_errors_total",
+            "Errors in the MCP adapter pipeline (transport, protocol, or serialization)."
+        )
+        .expect("computer_hub_mcp_errors_total must register once")
+    });
+
+    static MCP_TOOLS_BRIDGED: LazyLock<IntGauge> = LazyLock::new(|| {
+        register_int_gauge!(
+            "computer_hub_mcp_tools_bridged",
+            "MCP tools currently bridged into the computer hub."
+        )
+        .expect("computer_hub_mcp_tools_bridged must register once")
+    });
+
+    pub(crate) fn mcp_call_duration_observe(secs: f64) {
+        MCP_CALL_DURATION_SECONDS.observe(secs);
+    }
+
+    pub(crate) fn mcp_error() {
+        MCP_ERRORS_TOTAL.inc();
+    }
+
+    pub(crate) fn mcp_tools_bridged_set(count: i64) {
+        MCP_TOOLS_BRIDGED.set(count);
+    }
+}
+
+#[cfg(not(feature = "metrics"))]
+mod inner {
+    pub(crate) fn mcp_call_duration_observe(_secs: f64) {}
+    pub(crate) fn mcp_error() {}
+    pub(crate) fn mcp_tools_bridged_set(_count: i64) {}
+}
+
+pub(crate) use inner::*;