release: 0.7.6 (fix permission denied on global install)

The 0.7.5 tarball shipped `dist/bin/codegraph.js` without the executable
bit set, causing `zsh: permission denied: codegraph` after a fresh global
install. The build script now `chmod +x`'s the binary before packing.

Also adds CHANGELOG.md and documents the release workflow in CLAUDE.md.

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "@colbymchenry/codegraph",
-  "version": "0.7.2",
+  "version": "0.7.6",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@colbymchenry/codegraph",
-      "version": "0.7.2",
+      "version": "0.7.6",
       "license": "MIT",
       "dependencies": {
         "@clack/prompts": "^1.3.0",