Room code scrambling + personalization

[rcelyte]

Room codes should be randomized for private rooms and mapped to wire handles via hash accelerated table lookup, avoiding duplicate codes. A filter is needed to avoid unfortunate strings showing up in codes from any source: indexed, random, or custom set by the host. Additionally, the following characters should be aliased due to similar appearance in-game:

• B -> 8
• D -> 0
• I -> 1
• O -> 0