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/src/extensions/session_search.rs

@@ -0,0 +1,117 @@
+//! ACP extension handler for session search (`x.ai/session/search`).
+//!
+//! Exposes session full-text search as an ACP extension method.
+//! The client sends a query and receives ranked results across all
+//! (or workspace-filtered) past sessions.
+//!
+//! ```text
+//! JSON-RPC -> mvp_agent.ext_method()
+//!          -> session_search::handle()
+//!          -> storage::search::execute_search()
+//!          -> search_fts::SessionSearchIndex (SQLite FTS5)
+//! ```
+
+use agent_client_protocol as acp;
+use serde::{Deserialize, Serialize};
+
+use crate::session::storage::search::{SessionSearchRequest, SessionSearchResponse};
+use crate::session::storage::search_fts::SessionSearchRow;
+
+use super::ExtResult;
+
+#[derive(Debug, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct SearchSessionsRequest {
+    /// The search query string.
+    pub query: String,
+    /// Optional workspace directory to scope results to.
+    #[serde(default)]
+    pub cwd: Option<String>,
+    /// Maximum number of results to return. Defaults to 20.
+    #[serde(default = "default_limit")]
+    pub limit: usize,
+    /// Offset for pagination. Defaults to 0.
+    #[serde(default)]
+    pub offset: usize,
+    /// Whether to include content snippets in results.
+    #[serde(default)]
+    pub include_content: bool,
+}
+
+fn default_limit() -> usize {
+    20
+}
+
+#[derive(Debug, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct SearchSessionsResponse {
+    pub results: Vec<SearchSessionHit>,
+    pub next_offset: Option<usize>,
+    pub total_estimate: Option<usize>,
+    /// True when the FTS5 index is still being bootstrapped.
+    pub bootstrapping: bool,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct SearchSessionHit {
+    pub session_id: String,
+    pub cwd: String,
+    /// Session title/summary for display
+    pub summary: String,
+    /// RFC 3339 formatted updated_at
+    pub updated_at: String,
+    pub score: f32,
+    pub matched_fields: Vec<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub snippet: Option<String>,
+}
+
+/// Route `x.ai/session/search` extension method calls.
+pub async fn handle(args: &acp::ExtRequest) -> ExtResult {
+    match args.method.as_ref() {
+        "x.ai/session/search" => {
+            let req: SearchSessionsRequest = super::parse_params(args)?;
+            let internal_req = SessionSearchRequest {
+                query: req.query,
+                cwd: req.cwd,
+                limit: req.limit,
+                offset: req.offset,
+                include_content: req.include_content,
+            };
+
+            let root_dir = crate::util::kigi_home::kigi_home();
+            let result = crate::session::storage::search::execute_search(&root_dir, &internal_req)
+                .await
+                .map(to_response)
+                .map_err(|e| anyhow::anyhow!(e));
+
+            super::to_ext_response(result)
+        }
+        _ => Err(acp::Error::method_not_found()),
+    }
+}
+
+/// Convert the internal response to the ACP-facing response.
+fn to_response(resp: SessionSearchResponse) -> SearchSessionsResponse {
+    SearchSessionsResponse {
+        results: resp
+            .results
+            .into_iter()
+            .map(|row: SessionSearchRow| SearchSessionHit {
+                session_id: row.session_id,
+                cwd: row.cwd,
+                summary: row.title,
+                updated_at: chrono::DateTime::from_timestamp(row.updated_at_unix, 0)
+                    .map(|dt| dt.to_rfc3339())
+                    .unwrap_or_default(),
+                score: row.score,
+                matched_fields: row.matched_fields,
+                snippet: row.snippet,
+            })
+            .collect(),
+        next_offset: resp.next_offset,
+        total_estimate: resp.total_estimate,
+        bootstrapping: resp.bootstrapping,
+    }
+}