feat(data-masking): add data masking utility

Add new @aws-lambda-powertools/data-masking package with support for:
- Irreversible field erasure with default or custom masking rules
- Field-level and full-payload encryption/decryption via AWS Encryption SDK
- Encryption context for integrity and authenticity
- Dot notation and [*] wildcard field selection
- Prototype pollution protection

Includes unit tests with property-based testing (fast-check),
e2e test scaffolding, and user-facing documentation.

Author: svozza

.gitignore

@@ -53,4 +53,11 @@ tsconfig.tsbuildinfo
 .amazonq
 .kiro
 .github/instructions
-aidlc-docs
+aidlc-docsspecs/
+.specify/
+AGENTS.md
+# generated agent artifacts
+specs/
+.specify/
+AGENTS.md
+aidlc-docs/

.markdownlintignore

@@ -10,4 +10,7 @@ layers/*/CHANGELOG.md
 LICENSE
 .github/**
 **node_modules/** */
-.venv
+.venv
+# generated spec artifacts
+specs/**
+.specify/**