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/select.rs

@@ -0,0 +1,279 @@
+//! Turn selection for compaction.
+//!
+//! Walks the item list backward to find a split point: keep the newest items
+//! whose cumulative token count fits the target budget, compact everything
+//! older.
+//!
+//! The split point must respect a critical invariant: an assistant item with
+//! tool requests and the subsequent tool-result items that satisfy those
+//! requests must stay together. Splitting between them would produce orphan
+//! tool results in the next prompt, which the model API rejects with a 400.
+//!
+//! This is the harness-agnostic core: it operates over any slice of
+//! [`CompactionItem`], so both Grok chat (`GrokTurn`) and grok-build
+//! (`ConversationItem`) share one implementation.
+
+use crate::item::CompactionItem;
+
+/// Output of [`select_turns_to_compact`].
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct SplitPlan {
+    /// Compact items at indices `0..split_idx`. Keep `split_idx..total`.
+    pub split_idx: usize,
+    /// Sum of `item_token_counts[..split_idx]`.
+    pub tokens_to_compact: u32,
+}
+
+/// Decide where to split the items for compaction.
+///
+/// Algorithm:
+/// 1. Walk backward from the newest item, accumulating "keep" tokens.
+/// 2. The candidate split index is the first one where adding more would
+///    exceed `target_tokens`.
+/// 3. **Snap forward** to a safe boundary: if the split would orphan tool
+///    results, walk forward until past the matching tool-result items.
+/// 4. Return `None` if the resulting compactable region's token count is
+///    below `min_compactable` — not worth running the LLM.
+///
+/// # Tool-pair boundary safety
+///
+/// `items` is the agent's running state. A typical sequence:
+///
+/// ```text
+/// [Assistant(tool_request_A, tool_request_B),
+///  Tool(A_result),
+///  Tool(B_result),
+///  Assistant(response_text),
+///  Assistant(tool_request_C),
+///  Tool(C_result),
+///  ...]
+/// ```
+///
+/// A safe split point is one where everything **before** the split is
+/// self-contained (no dangling tool requests waiting for results that live
+/// after the split).
+///
+/// The rule we enforce: the split index must not fall in the middle of a
+/// `[Assistant-with-tool-requests, Tool, Tool, ...]` run. If the candidate
+/// split lands on a tool-result item, walk it forward until we pass the last
+/// tool-result item following the most recent assistant-with-tool-requests.
+pub fn select_turns_to_compact<T: CompactionItem>(
+    item_token_counts: &[u32],
+    items: &[T],
+    target_tokens: u32,
+    min_compactable: u32,
+) -> Option<SplitPlan> {
+    debug_assert_eq!(
+        item_token_counts.len(),
+        items.len(),
+        "token counts and items must have the same length"
+    );
+
+    let total = items.len();
+    if total == 0 {
+        return None;
+    }
+
+    // Step 1: Walk backward, sum "keep" tokens until target is reached.
+    // Find the highest split_idx such that sum(item_token_counts[split_idx..]) ≤ target_tokens.
+    let mut kept = 0u32;
+    let mut split_idx = total; // start with "compact nothing", will move down
+    for i in (0..total).rev() {
+        let count = item_token_counts[i];
+        if kept.saturating_add(count) > target_tokens {
+            // Adding this item would exceed the budget — split here.
+            split_idx = i + 1;
+            break;
+        }
+        kept = kept.saturating_add(count);
+        split_idx = i;
+    }
+
+    // If the whole list fits within the budget, nothing to compact.
+    if split_idx == 0 {
+        return None;
+    }
+
+    // Step 2: Snap the split forward to a safe boundary.
+    let safe_split_idx = snap_to_safe_boundary(items, split_idx);
+
+    // After snapping forward we might have eaten everything.
+    if safe_split_idx >= total {
+        return None;
+    }
+
+    // Step 3: Compute tokens to compact and check the minimum.
+    let tokens_to_compact: u32 = item_token_counts[..safe_split_idx]
+        .iter()
+        .copied()
+        .fold(0u32, u32::saturating_add);
+
+    if tokens_to_compact < min_compactable {
+        return None;
+    }
+
+    Some(SplitPlan {
+        split_idx: safe_split_idx,
+        tokens_to_compact,
+    })
+}
+
+/// If `candidate` lands on a tool-result item, advance forward past all
+/// tool-result items in the same tool-pair run. The "run" is delimited by the
+/// previous assistant item (with tool requests) and the next non-tool item.
+///
+/// In effect: ensure the split lands either right before an assistant, user,
+/// system, or developer item — never between an assistant-with-tool-requests
+/// and its tool results.
+fn snap_to_safe_boundary<T: CompactionItem>(items: &[T], candidate: usize) -> usize {
+    let total = items.len();
+    if candidate >= total {
+        return total;
+    }
+
+    // If candidate is not a tool-result item, no snap needed.
+    if !items[candidate].is_tool_result() {
+        return candidate;
+    }
+
+    // Candidate is a tool-result item. Find the run of contiguous tool-result
+    // items (starting from the assistant-with-tool-requests that preceded
+    // them) and advance to just past the last one in that run.
+    let mut idx = candidate;
+    while idx < total && items[idx].is_tool_result() {
+        idx += 1;
+    }
+    idx
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::item::CompactionRole;
+
+    /// Minimal mock implementing [`CompactionItem`] for selection tests.
+    struct MockItem {
+        role: CompactionRole,
+    }
+
+    impl MockItem {
+        fn user() -> Self {
+            Self {
+                role: CompactionRole::User,
+            }
+        }
+        fn assistant() -> Self {
+            Self {
+                role: CompactionRole::Assistant,
+            }
+        }
+        fn tool() -> Self {
+            Self {
+                role: CompactionRole::Tool,
+            }
+        }
+    }
+
+    impl CompactionItem for MockItem {
+        fn role(&self) -> CompactionRole {
+            self.role
+        }
+        fn text(&self) -> Option<String> {
+            None
+        }
+        fn has_tool_requests(&self) -> bool {
+            false
+        }
+        fn is_compaction_summary(&self) -> bool {
+            false
+        }
+        fn attachment_refs(&self) -> Vec<crate::item::CompactionFileRef> {
+            Vec::new()
+        }
+    }
+
+    #[test]
+    fn empty_returns_none() {
+        let items: Vec<MockItem> = vec![];
+        assert!(select_turns_to_compact(&[], &items, 100, 10).is_none());
+    }
+
+    #[test]
+    fn all_fits_in_budget_returns_none() {
+        let items = vec![MockItem::user(), MockItem::assistant()];
+        let counts = vec![10, 20];
+        assert!(select_turns_to_compact(&counts, &items, 1000, 5).is_none());
+    }
+
+    #[test]
+    fn splits_at_correct_index() {
+        // Total 100; target 30 → keep last few that fit in 30.
+        let items = vec![
+            MockItem::user(),
+            MockItem::assistant(),
+            MockItem::user(),
+            MockItem::assistant(),
+        ];
+        let counts = vec![40, 30, 20, 10]; // keep last two (sum 30)
+        let plan = select_turns_to_compact(&counts, &items, 30, 5).expect("should split");
+        assert_eq!(plan.split_idx, 2);
+        assert_eq!(plan.tokens_to_compact, 70);
+    }
+
+    #[test]
+    fn below_min_compactable_returns_none() {
+        let items = vec![MockItem::user(), MockItem::assistant()];
+        let counts = vec![5, 100];
+        // Would split after index 0, but 5 < min_compactable (10).
+        assert!(select_turns_to_compact(&counts, &items, 50, 10).is_none());
+    }
+
+    #[test]
+    fn snaps_past_tool_results() {
+        // Layout: [User, Assistant-text, Assistant-with-tools, Tool, Tool, Assistant-text]
+        // If the naïve split lands on a Tool, snap forward past all Tools.
+        let items = vec![
+            MockItem::user(),
+            MockItem::assistant(),
+            MockItem::assistant(), // pretend this had tool_requests
+            MockItem::tool(),
+            MockItem::tool(),
+            MockItem::assistant(),
+        ];
+        let counts = vec![10, 10, 10, 50, 50, 10];
+
+        // Target 60 → walking back: keep 10 (idx 5), keep 50 (idx 4)
+        // → 60 used. Adding idx 3 (50) overflows.
+        // Naïve split = 4. But items[4] is Tool → snap forward.
+        // Walk forward: items[4]=Tool, items[5]=Assistant → snap to 5.
+        let plan = select_turns_to_compact(&counts, &items, 60, 5).expect("should split");
+        assert_eq!(plan.split_idx, 5);
+        assert_eq!(plan.tokens_to_compact, 10 + 10 + 10 + 50 + 50);
+    }
+
+    #[test]
+    fn snap_does_not_advance_when_already_safe() {
+        let items = vec![
+            MockItem::user(),
+            MockItem::assistant(),
+            MockItem::user(), // safe split here
+            MockItem::assistant(),
+        ];
+        let counts = vec![50, 50, 10, 10];
+        // Target 30 → keep last two (sum 20).
+        // Naïve split = 2. items[2] = User → safe, no snap needed.
+        let plan = select_turns_to_compact(&counts, &items, 30, 5).expect("should split");
+        assert_eq!(plan.split_idx, 2);
+    }
+
+    #[test]
+    fn snap_walks_to_end_returns_none() {
+        // Pathological: split would need to snap past all items.
+        let items = vec![MockItem::assistant(), MockItem::tool(), MockItem::tool()];
+        let counts = vec![10, 50, 50];
+        // Target 0 → naïve split = 1 (items[1] is Tool).
+        // Snap forward: items[1]=Tool, items[2]=Tool, idx=3=total.
+        // Return None — nothing left to keep.
+        assert!(select_turns_to_compact(&counts, &items, 0, 5).is_none());
+    }
+}