Add skill-manager skill (migrated from skill-creator) with deploy action

- Skill content moved from ~/.agents/skills/skill-creator, renamed to skill-manager
- New deploy CLI action: installs any skill via absolute-path symlinks (or copies)
  into $HOME/.agents/skills, $HOME/.claude/skills and $HOME/.cline/skills
- Taskfile + shell module wrappers (task deploy / cli:deploy)
- SKILL.md: deploy docs, origin-repository/origin-path metadata

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

scripts/.scripts/base/lib/-ensure-environment-variable.sh

@@ -0,0 +1,18 @@
+#!/bin/bash
+# -------------------------------------------------------------------------------------
+#
+#
+#
+# -------------------------------------------------------------------------------------
+
+. ./.scripts/loggers/lib/--index-api.sh
+
+_base_ensureEnvironmentVariable() {
+  local FUNCTION_NAME="_base_ensureEnvironmentVariable"
+  local ENV_VAR_NAME="$1"
+  _loggers_info "${FUNCTION_NAME}" "ENV_VAR_NAME: ${ENV_VAR_NAME}"
+  if [ -z "${!ENV_VAR_NAME}" ]; then
+    _loggers_error "${FUNCTION_NAME}" "Missing required environment variable: ${ENV_VAR_NAME}. Check .env or .env-* files!"
+    exit 1
+  fi
+}