fix(android,ios,rn): standardize shell options and remove DEVBOX_COREPACK_ENABLED workaround

Sourced scripts (lib, platform, domain, init) now use `set -e` only.
Previously `set -eu` in sourced init hooks leaked `set -u` into devbox's
generated hooks shell, causing `DEVBOX_COREPACK_ENABLED: unbound variable`
when nodejs was included alongside plugins.

Executed scripts (CLI entry points) keep `set -eu` (POSIX sh) and test
scripts keep `set -euo pipefail` (bash) since they run in subprocesses
and cannot leak shell options.

With the root cause fixed, the DEVBOX_COREPACK_ENABLED="" workaround is
removed from devbox.json and plugin.json.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: abueide

devbox.json

@@ -12,8 +12,7 @@
     "REPORTS_DIR":      "reports",
     "TEST_RESULTS_DIR": "reports/results",
     "TEST_LOGS_DIR":    "reports/logs",
-    "TEST_TUI":         "false",
-    "DEVBOX_COREPACK_ENABLED": ""
+    "TEST_TUI":         "false"
   },
   "shell": {
     "scripts": {

examples/react-native/devbox.json

@@ -12,7 +12,6 @@
     "ANDROID_APP_ID": "com.reactnativeexample",
     "ANDROID_APP_APK": "android/app/build/outputs/apk/debug/app-debug.apk",
     "ANDROID_MAX_API": "35",
-    "DEVBOX_COREPACK_ENABLED": "",
     "ANDROID_SDK_REQUIRED": "0"
   },
   "shell": {

plugins/android/virtenv/scripts/domain/avd-reset.sh

@@ -2,7 +2,7 @@
 # Android Plugin - AVD Reset and Cleanup Operations
 # Extracted from avd.sh to eliminate circular dependencies
 
-set -eu
+set -e
 
 if ! (return 0 2>/dev/null); then
   echo "ERROR: avd_reset.sh must be sourced, not executed directly" >&2

plugins/android/virtenv/scripts/domain/avd.sh

@@ -2,7 +2,7 @@
 # Android Plugin - AVD Manager Operations
 # Extracted from avd.sh to eliminate circular dependencies
 
-set -eu
+set -e
 
 if ! (return 0 2>/dev/null); then
   echo "ERROR: avd_manager.sh must be sourced, not executed directly" >&2

plugins/android/virtenv/scripts/domain/build.sh

@@ -2,7 +2,7 @@
 # Android Plugin - Build Command
 # Auto-detects Gradle project and builds with sensible defaults
 
-set -eu
+set -e
 
 if ! (return 0 2>/dev/null); then
   echo "ERROR: build.sh must be sourced, not executed directly" >&2

plugins/android/virtenv/scripts/domain/deploy.sh

@@ -2,7 +2,7 @@
 # Android Plugin - Application Run
 # See SCRIPTS.md for detailed documentation
 
-set -eu
+set -e
 
 if ! (return 0 2>/dev/null); then
   echo "ERROR: deploy.sh must be sourced, not executed directly" >&2

plugins/android/virtenv/scripts/domain/emulator.sh

@@ -2,7 +2,7 @@
 # Android Plugin - Emulator Lifecycle Management
 # See SCRIPTS.md for detailed documentation
 
-set -eu
+set -e
 
 if ! (return 0 2>/dev/null); then
   echo "ERROR: emulator.sh must be sourced, not executed directly" >&2

plugins/android/virtenv/scripts/domain/validate.sh

@@ -3,7 +3,7 @@
 # See SCRIPTS.md for detailed documentation
 # Philosophy: Warn, don't block
 
-set -eu
+set -e
 
 # Validate that ANDROID_SDK_ROOT points to an existing directory (non-blocking)
 android_validate_sdk() {

plugins/android/virtenv/scripts/init/setup.sh

@@ -35,7 +35,7 @@ ANDROID_ENV_LOADED=1
 ANDROID_ENV_LOADED_PID="$$"
 export ANDROID_ENV_LOADED ANDROID_ENV_LOADED_PID
 
-set -eu
+set -e
 
 # ============================================================================
 # Source Dependencies

plugins/android/virtenv/scripts/lib/lib.sh

@@ -2,7 +2,7 @@
 # Android Plugin - Core Utilities
 # See SCRIPTS.md for detailed documentation
 
-set -eu
+set -e
 
 if ! (return 0 2>/dev/null); then
   echo "ERROR: lib.sh must be sourced" >&2