NOTEPOD: add test of new note creation #236

[Amoghhosamane]

@"

Pull Request Details

Description

This PR addresses issue #272 by replacing AES encryption of note content with
base64 encoding. Currently, note text is encrypted using the created time as an
AES key because rdflib cannot parse multiline text containing # (hash) values.

As suggested in #272, base64 encoding is a better alternative — it is simpler,
reversible, and still solves the rdflib parsing problem without the overhead or
security implications of encryption (since the "key" was just a timestamp anyway).

Changes:

• lib/utils/encryption.dart: encryptVal() now encodes plaintext using base64.
  decryptVal() now decodes from base64, with a fallback to AES decryption for
  backward compatibility with notes saved using the previous scheme.

Related Issues

Closes #272

Type of Change

• New feature (non-breaking change which adds functionality)

How To Test?

1. Open the app and sign in.
2. Create a new note with multiline content including # (hash) characters.
3. Save the note and verify it saves and displays correctly.
4. Open an existing note that was saved with the old scheme — it should still
   display correctly (backward-compatible AES fallback).

Checklist

• Screenshots included here/in linked issue #
• Changes adhere to the style and coding guidelines
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• Any dependent changes have been merged and published in downstream modules
• The update contains no confidential information
• The update has no duplicated content
• No lint check errors are related to these changes
• Integration test output included in issue #
• I tested the PR on these devices:
  • Android
  • iOS
  • Linux
  • MacOS
  • Windows
  • Web
• I have identified reviewers
• The PR has been approved by reviewers

Finalising

• Merge dev into this branch
• Resolve any conflicts
• Add a one line summary into the CHANGELOG.md
• Push to the git repository and review
• Merge the PR into dev
  "@