chore: drop NODE_COMPILE_CACHE convention

Removes the project-level NODE_COMPILE_CACHE="./.cache" pin from
.env.example and the now-redundant ".cache/**" excludes from both
tsconfigs. The compile-cache pollution at repo root is noise that
has no consumer in the codebase — vitest already writes its own
cache under node_modules/.cache/.

Author: jdalton

.env.example

@@ -2,7 +2,6 @@
 # Copy this file to .env.local and customize for your local environment.
 
 # Node.js Configuration (optional overrides).
-NODE_COMPILE_CACHE="./.cache"
 NODE_OPTIONS="--max-old-space-size=8192 --max-semi-space-size=1024"
 
 # Socket API Configuration (for e2e testing).

packages/cli/tsconfig.json

@@ -11,7 +11,6 @@
     "test/helpers/**/*.mts"
   ],
   "exclude": [
-    ".cache/**",
     ".claude/**",
     "build/**",
     "binaries/**",

tsconfig.json

@@ -15,7 +15,6 @@
     "binaries/**",
     "dist/**",
     "external/**",
-    ".cache/**",
     ".claude/**",
     "node_modules/**",
     "pkg-binaries/**"