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-sandbox/Cargo.toml

@@ -0,0 +1,64 @@
+[package]
+license = "Apache-2.0"
+name = "kigi-sandbox"
+version.workspace = true
+edition.workspace = true
+description = "OS-level sandboxing for Grok Build using kernel primitives (Landlock/Seatbelt) via nono"
+
+[dependencies]
+anyhow = { workspace = true }
+chrono = { workspace = true, features = ["serde"] }
+dirs = "5.0"
+dunce = { workspace = true }
+serde = { workspace = true }
+serde_json = { workspace = true }
+toml = { workspace = true }
+tracing = { workspace = true }
+kigi-config = { workspace = true }
+
+[target.'cfg(unix)'.dependencies]
+libc = { workspace = true }
+# Pinned exact: the macOS Seatbelt deny precedence (see deny.rs `emit_seatbelt_deny`)
+# depends on nono's observed rule-emission order. A bump can silently change it and
+# re-open the `mv x y && cat y` bypass with `is_applied()` still true, so re-verify
+# `deny_paths_e2e` on real macOS (it self-skips in CI) before bumping.
+#
+# Non-optional (not gated on `enforce`): Cargo has no target-conditional features
+# table, so a `dep:nono` reference from the cross-platform `enforce` feature would
+# break feature resolution on non-unix targets (e.g. Windows builds). nono/globset
+# are unix-only here, so they only compile on unix anyway; the enforce *code*
+# stays gated on `cfg(all(feature = "enforce", unix))`.
+nono = { version = "=0.53.0", default-features = false }
+# globset validates every deny glob on BOTH platforms (so a glob is interpreted
+# identically or rejected identically) and matches them on Linux. Non-optional for
+# the same reason as nono above.
+globset = { workspace = true }
+
+# Linux additionally walks the tree to expand globs to existing paths (enforce+
+# linux only). cfg(linux)-gated rather than enforce-gated: the cross-platform
+# enforce feature can't reference a linux-only optional dep without breaking macOS
+# feature resolution, so a `--no-default-features` Linux build pulls it unused.
+[target.'cfg(target_os = "linux")'.dependencies]
+ignore = { workspace = true }
+
+[features]
+default = ["enforce"]
+## Enable kernel-enforced sandboxing via nono (Landlock/Seatbelt). Marker feature
+## only: the backing deps (nono/globset) are non-optional unix-only deps (see
+## above), and the enforce code is gated on `cfg(all(feature = "enforce", unix))`.
+## On non-unix targets enabling this feature is a no-op (no kernel sandbox exists).
+enforce = []
+
+[dev-dependencies]
+serial_test = { workspace = true }
+# Compiles the hand-rolled macOS deny-glob regex in tests to assert it matches
+# EXACTLY the set globset (the Linux backend) matches — the cross-platform parity
+# guard for the glob dialect.
+regex = { workspace = true }
+
+# The smoke-test example exercises kernel enforcement (uses enforce-only APIs
+# like `support_info`), so it only builds with the `enforce` feature. This keeps
+# `--no-default-features --all-targets` clean.
+[[example]]
+name = "sandbox_smoke_test"
+required-features = ["enforce"]