Print placeholders instead of codewords by default

[t-animal]

With printers these days you never know what they store or where the documents they print go. Thus it would be insecure to print the whole shard-pdf (or, at least all shards) on a printer as the shard content could be recovered from it. Since there is already a shard password, it would make sense to not print it by default and have the user write it down manually. While this requires quite a bit of manual labor it is the only way I could figure out how to print the shards securely when designing a similar system.

[cyphar]

We can add a mode for people to write down the codewords but given that a mistake when copying them can lead to the shard becoming unusable I suspect it shouldn't be the default. Not to mention that you want to make sure the ink won't fade at a different rate to the printed ink and possible legibility issues.