refactor: consolidate external bundles and deduplicate dependencies

- Create external-pack.js bundling shared deps: signal-exit, supports-color,
  has-flag, yoctocolors-cjs, and all @InQuirer packages
- Remove inquirer-pack.js (merged into external-pack)
- Remove npm-core.js (merged into npm-pack)
- Remove debug stub to bundle real debug package
- Mark debug and which as external in npm-pack to avoid duplication
- Add pnpm overrides for version consolidation
- Update @InQuirer re-exports to use external-pack
- Update test to reflect new bundle structure

Author: jdalton

package.json

@@ -744,6 +744,7 @@
     "fast-sort": "3.4.1",
     "get-east-asian-width": "1.3.0",
     "globals": "16.4.0",
+    "has-flag": "5.0.1",
     "husky": "9.1.7",
     "libnpmexec": "^10.1.11",
     "libnpmpack": "9.0.9",
@@ -756,9 +757,11 @@
     "pacote": "21.0.1",
     "picomatch": "2.3.1",
     "semver": "7.7.2",
+    "signal-exit": "4.1.0",
     "spdx-correct": "3.2.0",
     "spdx-expression-parse": "4.0.0",
     "streaming-iterables": "8.0.1",
+    "supports-color": "10.0.0",
     "taze": "19.9.2",
     "trash": "10.0.0",
     "type-coverage": "2.29.7",
@@ -784,14 +787,23 @@
     "overrides": {
       "@npmcli/arborist": "9.1.6",
       "@npmcli/run-script": "10.0.0",
+      "@sigstore/core": "3.1.0",
       "@sigstore/sign": "4.1.0",
       "ansi-regex": "6.2.2",
+      "debug": "4.4.3",
+      "has-flag": "5.0.1",
+      "isexe": "3.1.1",
       "lru-cache": "11.2.2",
       "picomatch": "4.0.3",
+      "proc-log": "6.1.0",
       "semver": "7.7.2",
+      "signal-exit": "4.1.0",
       "string-width": "8.1.0",
       "strip-ansi": "7.1.2",
-      "wrap-ansi": "9.0.2"
+      "supports-color": "10.0.0",
+      "which": "5.0.0",
+      "wrap-ansi": "9.0.2",
+      "yoctocolors-cjs": "2.1.3"
     },
     "patchedDependencies": {
       "@npmcli/run-script@10.0.0": "patches/@npmcli__run-script@10.0.0.patch",