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-markdown/src/source_map.rs

@@ -0,0 +1,141 @@
+//! Source mapping for rendered markdown back to original source.
+//!
+//! Used for copy-paste operations: when the user selects rendered text,
+//! we can look up the corresponding original markdown source.
+
+use std::ops::Range;
+
+/// Maps rendered byte positions back to source byte positions.
+///
+/// Direction: rendered (new) → source (old)
+#[derive(Debug, Clone, Default)]
+pub struct SourceMap {
+    /// Segments: (rendered_range, source_range)
+    segments: Vec<(Range<usize>, Range<usize>)>,
+}
+
+impl SourceMap {
+    /// Create an empty source map.
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Add a mapping from rendered position to source position.
+    ///
+    /// The rendered text and source text must have the same length.
+    pub fn add(&mut self, rendered_start: usize, source_range: Range<usize>) {
+        let len = source_range.end - source_range.start;
+        if len > 0 {
+            self.segments
+                .push((rendered_start..rendered_start + len, source_range));
+        }
+    }
+
+    /// Given a rendered byte range, return the corresponding source range.
+    ///
+    /// Returns None if the range doesn't map cleanly (e.g., spans multiple
+    /// non-contiguous source regions).
+    pub fn to_source(&self, rendered: Range<usize>) -> Option<Range<usize>> {
+        let mut source_start = None;
+        let mut source_end = None;
+
+        for (r_range, s_range) in &self.segments {
+            if r_range.end <= rendered.start || r_range.start >= rendered.end {
+                continue;
+            }
+
+            let overlap_start = rendered.start.max(r_range.start);
+            let overlap_end = rendered.end.min(r_range.end);
+            let offset_start = overlap_start - r_range.start;
+            let offset_end = overlap_end - r_range.start;
+
+            let s_start = s_range.start + offset_start;
+            let s_end = s_range.start + offset_end;
+
+            source_start = Some(source_start.map_or(s_start, |v: usize| v.min(s_start)));
+            source_end = Some(source_end.map_or(s_end, |v: usize| v.max(s_end)));
+        }
+
+        match (source_start, source_end) {
+            (Some(s), Some(e)) => Some(s..e),
+            _ => None,
+        }
+    }
+
+    /// Check if the source map is empty.
+    pub fn is_empty(&self) -> bool {
+        self.segments.is_empty()
+    }
+
+    /// Get the number of segments.
+    pub fn len(&self) -> usize {
+        self.segments.len()
+    }
+
+    /// Extend with entries from another source map, applying offsets.
+    ///
+    /// Used when combining frozen content with newly rendered tail content.
+    pub fn extend_with_offsets(
+        &mut self,
+        other: &Self,
+        rendered_offset: usize,
+        source_offset: usize,
+    ) {
+        for (r_range, s_range) in &other.segments {
+            self.segments.push((
+                (r_range.start + rendered_offset)..(r_range.end + rendered_offset),
+                (s_range.start + source_offset)..(s_range.end + source_offset),
+            ));
+        }
+    }
+
+    /// Get read-only access to segments for inspection.
+    pub fn segments(&self) -> &[(Range<usize>, Range<usize>)] {
+        &self.segments
+    }
+
+    /// Truncate to keep only the first `n` segments.
+    pub fn truncate(&mut self, n: usize) {
+        self.segments.truncate(n);
+    }
+
+    /// Clear all segments.
+    pub fn clear(&mut self) {
+        self.segments.clear();
+    }
+}
+
+// ## Restoring Byte-Level Source Maps (if ever needed)
+//
+// The ratatui rendering path currently only tracks line-level source mapping
+// (`line_source_map`), which is sufficient for copy/selection operations.
+// Byte-level `SourceMap` was removed for simplicity and ~6% speedup.
+//
+// To restore byte-level source maps:
+//
+// 1. Add field to MarkdownRenderOutput and MarkdownRenderView:
+//    ```
+//    pub source_map: SourceMap,
+//    ```
+//
+// 2. In render_ratatui(), add tracking variables:
+//    ```
+//    let mut source_map = SourceMap::new();
+//    let mut rendered_offset: usize = 0;
+//    ```
+//
+// 3. For each text segment emitted, record the mapping:
+//    ```
+//    source_map.add(rendered_offset, source_start..source_end);
+//    rendered_offset += emitted_text.len();
+//    ```
+//
+// 4. In streaming.rs, update FrozenState to track:
+//    ```
+//    source_map_len: usize,
+//    rendered_bytes: usize,
+//    ```
+//
+// 5. Use SourceMap::extend_with_offsets() to merge tail source maps.
+//
+// See git history for the removed implementation.