sco-core SDK 2.2.0

See the SDK 2.2.0 release notes and the
SDK 2.2.0 scope decision.

SDK 2.2.0 packages the entries below without changing frozen plugin ABI 1.1
(include/sco_api.h and tests/abi_v1.c are byte-identical to 2.1.0). Core, legacy,
core-source and host-source-sc use 2.2.0. The maintainer kept the three new game service tables
in the candidate, so under the game-pack policy (a release that adds or grows
a game service raises the minor) the game pack and the optional game-sc overlay move to 0.5.0
(SCO_GAME_PACK_VERSION, was 0.4.0; sco-sdk-game-sc-0.5.0.zip). Nothing below
has run in the game: evidence is macOS local builds and synthetic fixtures. Linux, native
Windows, GPU and real-game acceptance are unproven. The new game capabilities
(game.hangar.lift, game.hangar.atc_cancel, game.reputation.checks,
game.world.free_camera_flag) default OFF, and no production adapter turns them on.

• sco.widgets 1.1 (additive): the table grows from 24 to 48 bytes with tail members
  update_nodes (atomic subtree replace/insert), remove_nodes (refuses to empty a panel) and
  capabilities (runtime limits by fixed index). Opt-in sco_widget_node_1_1 (severity,
  tooltip, paged LIST/TABLE windows) and sco_widget_event_1_1 (row; new SCO_WIDGET_EVENT_PAGE)
  are selected by their size field; panels without a 1.1 node keep byte-identical 1.0 events.
  The ImGui adapter draws severity, tooltips and Previous/Next paging, and rebuilds a shared
  render snapshot only when a panel changes. 1.0 pins are unchanged except the table size.
  sco-plugin-check remains a 1.0 stand-in; the C++, C# and Lua wrappers expose 1.0 only.
  Headless ImGui-shim fixtures only; GPU rendering not verified.
• C++ scosdk::PanelBuilder (include/scosdk/menu_builder.hpp): header-only C++20
  declarative Row/Column panels for sco.widgets 1.0 with typed bindings, preorder ids,
  host-equivalent ValidateWidgetNodes and callback dispatch that tolerates a callback
  destroying its own tree. Compared with the real host on 27 node arrays; ASan clean.
• C# Sco.Sdk.PanelBuilder: fluent Column/Row/Button/Toggle/Slider builder over
  sco.widgets 1.0 with explicit stable ids, frozen build snapshots and typed dispatch.
  Not compiled locally (no .NET SDK on the preparing host); the hosted
  sdk/csharp-host-sim job is its first build.
• Lua sco.panel_builder: embedded module installed in every plugin sandbox (new(),
  column/row, toggle/slider/button, build() returning node snapshots plus a
  dispatcher). Runs inside the existing instruction and memory budgets; no require,
  filesystem or bytecode.
• POSIX diagnostics transport recovery: an owner that died without cleanup no longer
  blocks every later session. The mapping is published atomically and held under flock; a
  stale entry is reclaimed only by the holder of its lock after identity re-checks, peers refuse
  a dead owner's mapping, and peer leases are removed on release. Fails closed on the remaining
  crash windows. macOS only; Linux unverified.
• Game status registry (repository only): sdk/status_registry.json generates the service
  table in docs/game/status.md; tools/status_registry.py --check runs in test.yml. No
  evidence level was raised.
• Documentation gate: the public documentation set must name the function, table or test
  instead of citing source by line number. A scheduled, read-only live-site job in
  docs-site.yml checks that the deployed docs site is fresh against main.
• Game tables (game-sc headers, host-source-sc implementation): game.hangar 1.0
  (include/sc_hangar.h: lift open/close request for a landing area, ATC request cancel),
  game.reputation 1.0 (include/sc_reputation.h: read-only state of the reputation check
  sites) and game.world 1.1 (include/sc_world.h grows 32 to 40 bytes with the read-only
  free_camera_flag tail member). ABI pins in tests/abi_game_hangar.c,
  tests/abi_game_reputation.c and tests/abi_game_world.c; host-sim contract tests
  hangar, reputation and world_free_cam. Windows game-pack adapters are not built or run
  locally; no wrapper language exposes these tables yet.
• Plugin scaffolder (sdk/tools/sco-new-plugin.py, shipped as tools/sco-new-plugin.py in
  core and core-source): writes a buildable C or C++20 native plugin with optional
  --with-menu panel and optional service lookups (logged when missing, never required), and
  its CMake check target runs sco-plugin-check. It refuses to overwrite files or write
  through symbolic links. sdk/test_new_plugin.py builds the generated projects on macOS; it
  is not wired into CI yet and MSVC builds are unverified.
• Engine-native index (repository, site and MCP only, in no SDK zip): sdk/native_index.json
  lists every signature row by id, subsystem, symbolic hash and promotion tier, generated by
  tools/native_index.py and checked in test.yml. The docs site renders it at /natives/
  inside four new library hubs, with a downloadable copy of the same JSON. Rows name readiness
  only: no patterns, masks, offsets or addresses. Publication follows the
  2026-10-14 native-index decision.
• Discovery MCP server, opt-in tools (repository only): tools/sco-core-mcp offers four
  tools behind --extended-tools; the default six tools and the documented launcher are
  unchanged. list_engine_natives and get_engine_native read sdk/native_index.json and
  refuse a malformed index whole. validate_manifest_and_widgets ports the sco-plugin-check
  manifest rules and checks sco.widgets node arrays. generate_plugin_scaffold returns the
  files sco-new-plugin.py would write as text and writes nothing; it runs the granted
  checkout's scaffolder in the server's own process, so grant only a reviewed checkout.
  Service evidence now prefers sdk/status_registry.json and never reports gameplay
  verification.
• Docs site: pages are grouped into four library hubs (start and SDK profiles, language
  SDKs and cookbooks, native and service reference, host integration and AI agents) with no
  route moved. Page titles no longer show code backticks.
• Getting started: docs/getting-started.md downloads, verifies and builds against the
  2.2.0 core archive; the game extension is sco-sdk-game-sc-0.5.0.zip.