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-workspace/src/error.rs

@@ -0,0 +1,86 @@
+//! Workspace error types.
+
+use crate::capability::CapabilityMode;
+
+/// Errors surfaced by the workspace public API.
+///
+/// `#[non_exhaustive]` so adding new variants is a non-breaking change.
+/// Tests should match on variants rather than scrape the `Display` text.
+#[derive(Debug, thiserror::Error)]
+#[non_exhaustive]
+pub enum WorkspaceError {
+    #[error("parent session not found: {0}")]
+    ParentSessionNotFound(String),
+
+    #[error("session not found: {0}")]
+    SessionNotFound(String),
+
+    #[error("session already exists: {0}")]
+    SessionAlreadyExists(String),
+
+    #[error("agent_id must be non-empty")]
+    EmptyAgentId,
+
+    #[error("the main session cannot be dropped")]
+    CannotDropMainSession,
+
+    #[error("toolset finalization failed: {0}")]
+    Finalize(String),
+
+    #[error("capability widening rejected: child {child:?} is not a subset of parent {parent:?}")]
+    CapabilityWidening {
+        parent: CapabilityMode,
+        child: CapabilityMode,
+    },
+
+    #[error("session {caller:?} is not authorised to operate on session {target:?}")]
+    Unauthorized { caller: String, target: String },
+
+    /// A toolset mutation was rejected because the target session has an
+    /// active turn. Retryable at the turn boundary (`after_turn`).
+    #[error("turn active for session {0}; retry the tool-config update at the turn boundary")]
+    TurnActive(String),
+
+    #[error("maximum fork depth exceeded for parent session {parent:?}")]
+    MaxDepthExceeded { parent: String },
+
+    #[error("internal task failure: {0}")]
+    JoinError(String),
+
+    #[error("invalid hunk action: {0}")]
+    InvalidHunkAction(String),
+
+    #[error("hunk action failed: {0}")]
+    HunkActionFailed(String),
+
+    /// An error from the server connection or tool server.
+    #[error("hub error: {0}")]
+    HubError(String),
+
+    /// Deploy-service error tagged with its gRPC status class; see
+    /// [`DeployError`] for how the class crosses the workspace RPC boundary.
+    ///
+    /// [`DeployError`]: kigi_workspace_types::rpc::deploy::DeployError
+    #[error("deploy error: {message}")]
+    DeployError {
+        kind: kigi_workspace_types::rpc::deploy::DeployError,
+        message: String,
+    },
+
+    /// The workspace is draining/shutting down and is no longer accepting new
+    /// sessions. Surfaced when a `bind`/create races a terminal drain so the
+    /// shared upload queue is never torn down out from under a fresh session.
+    #[error("workspace is shutting down; not accepting new sessions")]
+    ShuttingDown,
+
+    /// The session's toolset is externally owned — installed by a local
+    /// (shell) bind, its `Terminal` resource is not the session-owned
+    /// backend — so an RPC-driven toolset mutation is refused instead of
+    /// silently skipped. Hard error: retrying cannot succeed while the
+    /// local bind holds the toolset.
+    #[error("toolset externally owned (local bind), mutation refused: {0}")]
+    ToolsetExternallyOwned(String),
+}
+
+/// Convenience alias for the workspace's primary `Result` type.
+pub type WorkspaceResult<T> = Result<T, WorkspaceError>;