feat: redact

[zxch3n]

Redacts sensitive content within the specified version range by replacing it with default values.

Resolve #388

This method applies the following redaction rules:

• Preserves delete and move operations without changes
• Replaces text insertion content with the Unicode replacement character (U+FFFD)
• Substitutes list and map insert values with LoroValue::Null
• Maintains child container creation operations
• Replaces text mark values with LoroValue::Null
• Preserves map insertion and text annotation keys
• Resets counter operations to zero
• Leaves unknown operation types (from future Loro versions) unchanged

This approach ensures sensitive data removal while preserving the document's overall
structure. Redacted documents maintain seamless collaboration capabilities with both
redacted and non-redacted versions.

Example

    let doc = LoroDoc::new();
    doc.set_peer_id(1).unwrap();
    let text = doc.get_text("text");
    //              |-----------------------| <- 24 ops
    text.insert(0, "Hello, world! This is a secret message.")
        .unwrap();

    let mut json = doc.export_json_updates(&Default::default(), &doc.oplog_vv());
    let mut range = VersionRange::new();
    range.insert(1, 24, 30);
    redact(&mut json, range).unwrap();
    let redacted_doc = LoroDoc::new();
    redacted_doc.import_json_updates(json).unwrap();
    let redacted_text = redacted_doc.get_text("text");
    assert_eq!(
        redacted_text.to_string(),
        "Hello, world! This is a ������ message."
    );
    assert_ne!(text.to_string(), redacted_text.to_string());