chore: align editor config and simplify (#7551)

Simplifies and aligns the editor configuration so formatting rules are
consistent and editor-agnostic where possible.

- Moved spell-check dictionary from .vscode/settings.json to a standalone
  .cspell.json so it works across all editors, not just VSCode.
- Added .vscode/extensions.json recommending the EditorConfig and Code
  Spell Checker extensions to new contributors.
- Simplified .vscode/settings.json by removing contentious per-language
  formatter overrides and ESLint-as-default-formatter config.
- Removed the markdown exception in .editorconfig that disabled
  trim_trailing_whitespace for *.md files, making the rules uniform across
  all file types.

Motivation

- Align VSCode editor config with .editorconfig file (VSCode users don't
  automatically load this file without a custom plugin)
- Remove contentious entries from VSCode config

Author: watson

.cspell.json

@@ -0,0 +1,18 @@
+{
+  "$schema": "https://raw.githubusercontent.com/streetsidesoftware/cspell/main/cspell.schema.json",
+  "version": "0.2",
+  "language": "en",
+  "words": [
+    "aerospike",
+    "appsec",
+    "backportability",
+    "ddsource",
+    "kafkajs",
+    "llmobs",
+    "microbenchmarks",
+    "oracledb",
+    "rabbitmq",
+    "rspack",
+    "sirun"
+  ]
+}

.editorconfig

@@ -9,6 +9,3 @@ end_of_line = lf
 charset = utf-8
 trim_trailing_whitespace = true
 insert_final_newline = true
-
-[*.md]
-trim_trailing_whitespace = false

.vscode/extensions.json

@@ -0,0 +1,6 @@
+{
+  "recommendations": [
+    "EditorConfig.EditorConfig",
+    "streetsidesoftware.code-spell-checker"
+  ]
+}

.vscode/settings.json

@@ -1,40 +1,16 @@
 {
-  // Use the workspace version of TypeScript instead of VSCode's bundled version
-  "typescript.tsdk": "node_modules/typescript/lib",
+  // Core VSCode settings
+  "editor.formatOnSave": true,
+  "editor.insertSpaces": true,
+  "editor.tabSize": 2,
+  "files.eol": "\n",
   "files.insertFinalNewline": true,
-  "yaml.schemas": {
-    "https://json.schemastore.org/github-workflow.json": ".github/workflows/*.yml"
-  },
+  "files.trimTrailingWhitespace": true,
   "typescript.enablePromptUseWorkspaceTsdk": true,
-  "cSpell.words": [
-    "aerospike",
-    "appsec",
-    "backportability",
-    "ddsource",
-    "kafkajs",
-    "llmobs",
-    "microbenchmarks",
-    "oracledb",
-    "rabbitmq",
-    "rspack",
-    "sirun"
-  ],
-  "editor.defaultFormatter": "dbaeumer.vscode-eslint",
-  "editor.formatOnSave": true,
+  "typescript.tsdk": "node_modules/typescript/lib", // Use the workspace version of TypeScript instead of VSCode's bundled version
+  // Extension settings
   "eslint.format.enable": true,
-  "[javascript]": {
-    "editor.defaultFormatter": "dbaeumer.vscode-eslint",
-    "editor.codeActionsOnSave": {
-      "source.fixAll.eslint": "explicit"
-    }
-  },
-  "[typescript]": {
-    "editor.defaultFormatter": "dbaeumer.vscode-eslint",
-    "editor.codeActionsOnSave": {
-      "source.fixAll.eslint": "explicit"
-    }
-  },
-  "[json]": {
-    "editor.defaultFormatter": "vscode.json-language-features"
+  "yaml.schemas": {
+    "https://json.schemastore.org/github-workflow.json": ".github/workflows/*.yml"
   }
 }