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-compaction/src/sampler.rs

@@ -0,0 +1,184 @@
+//! The `CompactionSampler` seam — the LLM call that produces summaries —
+//! plus its output and error types (shared failure classification).
+
+use std::time::Duration;
+
+use async_trait::async_trait;
+
+use crate::prompt::CompactionPrompt;
+
+// ---------------------------------------------------------------------------
+// Sampler output + error types
+// ---------------------------------------------------------------------------
+
+/// Raw text captured from a compaction LLM call, split by channel.
+///
+/// Used by both intra- and inter-compaction. Intra-compaction uses only
+/// `.response`; inter-compaction also persists `.thinking` for audit/debug.
+#[derive(Debug, Default, Clone)]
+pub struct LlmCompactionOutput {
+    /// Text from the response channel — the actual compaction summary.
+    pub response: String,
+    /// Text from the thinking channel — the model's chain-of-thought reasoning.
+    /// Stored for audit/debug only; never fed back into a conversation.
+    pub thinking: String,
+}
+
+/// Error types for compaction sampling, allowing callers to distinguish
+/// deterministic failures (never retry) from transient ones.
+///
+/// Harnesses should prefer the structured variants ([`Self::Build`],
+/// [`Self::Start`], [`Self::EmptyResponse`]) so the shared retry policy can
+/// classify without string matching. [`Self::Other`] remains for samplers
+/// that only surface an opaque error; the orchestrator falls back to
+/// matching the literal messages produced by the Grok chat sampler —
+/// keep those literals in sync (the `compaction_sample_error_to_intra*`
+/// tests guard the mapping).
+#[derive(Debug)]
+pub enum CompactionSampleError {
+    /// The sampler hit its end-to-end timeout. Transient.
+    Timeout {
+        timeout_secs: u64,
+        collected_bytes: usize,
+    },
+    /// Sampler construction failed (bad config, unknown model). Deterministic.
+    Build(String),
+    /// The sampling call could not be started.
+    ///
+    /// Classification is asymmetric for pre-migration parity: the *inter*
+    /// retry policy ([`Self::is_deterministic`]) treats it as deterministic
+    /// (no retry), while the *intra* orchestrator maps it to
+    /// `IntraCompactionError::SamplerStart` which its retry loop treats as
+    /// transient.
+    Start(String),
+    /// The model produced no response-channel content. Transient.
+    EmptyResponse,
+    /// Anything else — classified by string matching for backward
+    /// compatibility with samplers that pre-date the structured variants.
+    Other(anyhow::Error),
+}
+
+impl std::fmt::Display for CompactionSampleError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::Timeout {
+                timeout_secs,
+                collected_bytes,
+            } => write!(
+                f,
+                "Compaction sampling timed out after {}s (collected {} bytes so far)",
+                timeout_secs, collected_bytes
+            ),
+            Self::Build(msg) => write!(f, "Compaction sampler build failed: {}", msg),
+            Self::Start(msg) => write!(f, "Compaction sampler start failed: {}", msg),
+            // Keep the "no response channel content" literal — the intra
+            // orchestrator's `Other(_)` fallback string-matches it.
+            Self::EmptyResponse => {
+                write!(f, "Compaction sampler returned no response channel content")
+            }
+            Self::Other(e) => write!(f, "{}", e),
+        }
+    }
+}
+
+impl From<anyhow::Error> for CompactionSampleError {
+    fn from(e: anyhow::Error) -> Self {
+        Self::Other(e)
+    }
+}
+
+impl CompactionSampleError {
+    /// Whether this error is deterministic — retrying with the same input
+    /// will produce the same failure.
+    pub fn is_deterministic(&self) -> bool {
+        match self {
+            Self::Timeout { .. } | Self::EmptyResponse => false,
+            Self::Build(_) | Self::Start(_) => true,
+            Self::Other(err) => {
+                let msg = err.to_string();
+                msg.contains("Failed to build AgenticScheduler")
+                    || msg.contains("Failed to start compaction sample")
+            }
+        }
+    }
+}
+
+// ---------------------------------------------------------------------------
+// Sampler trait
+// ---------------------------------------------------------------------------
+
+/// Interface for the LLM call that produces compaction summaries.
+///
+/// Used by both intra-compaction (steps/history) and inter-compaction.
+/// Implemented by each harness's sampler adapter; grok-build wires its own
+/// transport.
+///
+/// Returns [`LlmCompactionOutput`] containing both response and thinking
+/// channel text. Intra-compaction uses only `.response`; inter-compaction
+/// also persists `.thinking` for audit/debug.
+#[async_trait]
+pub trait CompactionSampler: Send + Sync {
+    /// The harness's conversation item type.
+    type Item;
+
+    /// Run an LLM compaction call on the given items.
+    ///
+    /// Implementations should:
+    /// - Build a synthetic conversation from the items + prompt.
+    /// - Honor the `timeout`.
+    /// - Collect both response and thinking channel text.
+    async fn sample_compaction(
+        &self,
+        turns: &[Self::Item],
+        prompt: &CompactionPrompt,
+        timeout: Duration,
+    ) -> Result<LlmCompactionOutput, CompactionSampleError>;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    /// Pins the inter-compaction retry classification for every variant —
+    /// `Start` is intentionally deterministic here (no inter retry) even
+    /// though the intra orchestrator retries its `SamplerStart` mapping.
+    /// See the doc on [`CompactionSampleError::Start`] before "fixing" this.
+    #[test]
+    fn is_deterministic_classification() {
+        assert!(
+            !CompactionSampleError::Timeout {
+                timeout_secs: 1,
+                collected_bytes: 0
+            }
+            .is_deterministic()
+        );
+        assert!(!CompactionSampleError::EmptyResponse.is_deterministic());
+        assert!(CompactionSampleError::Build("bad config".into()).is_deterministic());
+        assert!(CompactionSampleError::Start("no stream".into()).is_deterministic());
+        // Legacy string-matching fallback.
+        assert!(
+            CompactionSampleError::Other(anyhow::anyhow!(
+                "Failed to build AgenticScheduler: config error"
+            ))
+            .is_deterministic()
+        );
+        assert!(
+            CompactionSampleError::Other(anyhow::anyhow!(
+                "Failed to start compaction sample: stream error"
+            ))
+            .is_deterministic()
+        );
+        assert!(
+            !CompactionSampleError::Other(anyhow::anyhow!("transient stream error"))
+                .is_deterministic()
+        );
+    }
+
+    /// The `EmptyResponse` Display must keep the "no response channel
+    /// content" literal the intra `Other(_)` fallback string-matches.
+    #[test]
+    fn empty_response_display_keeps_match_literal() {
+        let msg = CompactionSampleError::EmptyResponse.to_string();
+        assert!(msg.contains("no response channel content"), "got: {msg}");
+    }
+}