Add vscode settings for local dkcoder dev

.gitignore

@@ -2,3 +2,10 @@
 /_build/dksdk-cmd-exe.log
 # ./dk dksdk.android.studio.download
 /.ci/local/share/Android Studio.app/
+
+# ./dk DkRun
+/#s/
+/_build/
+/.merlin
+/.z-dk-dune-project
+/dune-workspace

.vscode/settings.json

@@ -1,5 +1,10 @@
 {
     "cmake.configureOnOpen": false,
+    "ocaml.sandbox": {
+        "kind": "custom",
+        // SYNC: src/DkStd_Std/README.md, .vscode/settings.json, cmake/scripts/dkcoder/project/init.cmake
+        "template": "${firstWorkspaceFolder}/dk.cmd DkRun_V2_2.RunQuiet --log-level ERROR --fixed-length-modules false -- MlStd_Std.Exec --merlin -- $prog $args"
+    },
     "psi-header.config": {
         "forceToTop": true,
         "blankLinesAfter": 1

cmake/scripts/dkcoder/project/init.cmake

@@ -116,6 +116,7 @@ macro(dkcoder_project_init)
 
     set(init_OPTIONS)
     # all DkStd_Std commands must run in old versions of DkCoder. Confer dkcoder/src/DkStd_Std/README.md
+    #   SYNC: src/DkStd_Std/README.md, .vscode/settings.json, cmake/scripts/dkcoder/project/init.cmake
     set(dk_run DkRun_V2_2.RunAway)
     if(NOT ARG_QUIET)
         string(APPEND init_OPTIONS " -verbose")

src/DkStd_Std/README.md

@@ -5,8 +5,10 @@ because it is a source code compile, and because `./dk` has a TTL-cache
 based upgrade mechanism.
 
 That also means that the `Dk` library must run in old versions of DkCoder.
-That old version is DkCoder 2.2, and is hardcoded into
+<!-- SYNC: src/DkStd_Std/README.md, .vscode/settings.json, cmake/scripts/dkcoder/project/init.cmake -->
+That old version is DkCoder 2.2, and `DkRun_V2_2` is hardcoded into
 [cmake/scripts/dkcoder/project/init.cmake:dkcoder_project_init](../../cmake/scripts/dkcoder/project/init.cmake#dkcoder_project_init)
+and (less important) in [.vscode/settings.json](../../.vscode/settings.json).
 
 The unresolved difficulty is that `dk.sqlite3` metadata is not yet
 backwards-compatible. Backwards-compatibility is required.