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-interjection-core/src/format.rs

@@ -0,0 +1,60 @@
+/// Truncation threshold, matching the shell's large-prompt limit.
+pub const LARGE_PROMPT_THRESHOLD: usize = 25_000;
+
+/// Wrap a user message in the canonical `<user_query>` envelope.
+pub fn user_query(user_message: &str) -> String {
+    format!(
+        r#"<user_query>
+{user_message}
+</user_query>"#
+    )
+}
+
+/// Wrap interjection text as a synthetic user message with a mid-turn note.
+/// No deferral instruction: the model decides how to weigh it against
+/// in-flight work. Output is byte-identical to the shell's historical format.
+pub fn format_interjection(text: String) -> String {
+    let truncated = if text.len() > LARGE_PROMPT_THRESHOLD {
+        let end = text
+            .char_indices()
+            .take_while(|(i, _)| *i < LARGE_PROMPT_THRESHOLD)
+            .last()
+            .map(|(i, c)| i + c.len_utf8())
+            .unwrap_or(text.len());
+        format!("{}... [truncated]", &text[..end])
+    } else {
+        text
+    };
+
+    format!(
+        "The user sent a message while you were working:\n{}",
+        user_query(&truncated)
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn wraps_in_user_query_with_midturn_note() {
+        let out = format_interjection("stop and fix the test first".into());
+        assert!(out.starts_with("The user sent a message while you were working:\n<user_query>\n"));
+        assert!(out.ends_with("\n</user_query>"));
+        assert!(out.contains("stop and fix the test first"));
+    }
+
+    #[test]
+    fn truncates_at_utf8_boundary() {
+        let s = "é".repeat(LARGE_PROMPT_THRESHOLD);
+        let out = format_interjection(s);
+        assert!(out.contains("... [truncated]"));
+        assert!(out.len() < LARGE_PROMPT_THRESHOLD + 200);
+    }
+
+    #[test]
+    fn short_text_untouched() {
+        let out = format_interjection("hi".into());
+        assert!(!out.contains("[truncated]"));
+    }
+}