Replace PATH injection with post-install executable.path auto-config

Drops the cross-platform PATH-injection workaround in favor of probing
claude availability after install and writing the known install location
to claudeCodeChat.executable.path when it's not on PATH. Terminals for
login/model/usage/slash commands now launch claude directly via
createTerminal's shellPath/shellArgs so they work identically across
PowerShell, cmd, bash, and zsh. WSL nodePath is now optional (recent
Claude ships as a native binary) and its field moved below claudePath.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "claude-code-chat",
-  "version": "1.0.0",
+  "version": "2.0.6",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "claude-code-chat",
-      "version": "1.0.0",
+      "version": "2.0.6",
       "license": "SEE LICENSE IN LICENSE",
       "devDependencies": {
         "@types/mocha": "^10.0.10",