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-tool-runtime/src/search.rs

@@ -0,0 +1,83 @@
+//! Backend-agnostic tool search interface.
+//!
+//! `ToolSearchIndex` is a `Send + Sync` trait so concrete implementations
+//! can live in different crates (BM25, OpenSearch, in-memory linear) and
+//! be stored as `Arc<dyn ToolSearchIndex>` for shared access across tasks.
+
+use std::sync::Arc;
+
+/// A single tool search hit.
+#[derive(Debug, Clone, PartialEq)]
+pub struct ToolSearchResult {
+    /// Qualified tool name (e.g. `"linear__save_issue"`).
+    pub tool_name: String,
+    /// Origin server name (e.g. `"linear"`).
+    pub server_name: String,
+    /// Tool description.
+    pub description: String,
+    /// Backend-defined relevance score; comparable within a single
+    /// snapshot but not across snapshots.
+    pub score: f32,
+    /// Parameter names from the tool's input schema, in declaration order.
+    pub parameters: Vec<String>,
+    /// Full JSON Schema for the tool's input. Included so callers can
+    /// construct dispatched tool calls without a separate schema fetch.
+    pub input_schema: serde_json::Value,
+}
+
+/// Snapshot of a search query — results plus index metadata captured from
+/// the same point-in-time view.
+#[derive(Debug, Clone, PartialEq)]
+pub struct SearchSnapshot {
+    pub results: Vec<ToolSearchResult>,
+    /// Number of indexed tools that did not appear in `results`.
+    pub total_hidden_tools: usize,
+    /// `true` when the index reflects all available tools. `false` while
+    /// the index source is still warming up.
+    pub is_ready: bool,
+}
+
+/// Summary of an MCP server (or other tool source) available for search.
+#[derive(Debug, Clone, PartialEq)]
+pub struct ServerSummary {
+    /// Server name (e.g. `"linear"`, `"slack"`).
+    pub name: String,
+    /// Optional short description of the server's surface area.
+    pub description: Option<String>,
+    /// Unqualified tool names, sorted alphabetically. Use
+    /// [`Self::tool_count`] for a count without indirection.
+    pub tool_names: Vec<String>,
+}
+
+impl ServerSummary {
+    /// Number of tools the server exposes.
+    pub fn tool_count(&self) -> usize {
+        self.tool_names.len()
+    }
+}
+
+/// Backend-agnostic search interface.
+///
+/// Implementations must be `Send + Sync` so they can be wrapped in
+/// `Arc<dyn ToolSearchIndex>` and shared across concurrent tasks.
+pub trait ToolSearchIndex: Send + Sync {
+    /// Run a query against a single consistent index snapshot. Returning
+    /// the metadata alongside the results lets the caller render an
+    /// accurate "N results out of M" line without a second call.
+    fn search_snapshot(&self, query: &str, limit: usize) -> SearchSnapshot;
+
+    /// Enumerate the unique servers in the index. Used to render the
+    /// system-reminder listing connected integrations.
+    fn list_server_summaries(&self) -> Vec<ServerSummary>;
+}
+
+/// Resource wrapper for storing a `ToolSearchIndex` behind an `Arc` in
+/// shared resource maps.
+#[derive(Clone)]
+pub struct ToolIndex(pub Arc<dyn ToolSearchIndex>);
+
+impl std::fmt::Debug for ToolIndex {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("ToolIndex").finish()
+    }
+}