Add DNS first-seen and last-seen history

[jdjioe5-cpu]

Fixes #1

Summary:

• Adds DNS record history metadata: first-seen, last-seen, and seen.
• Preserves historical DNS records in the JSON output when they are missing from the current run.
• Adds --fs, --ls <days>, and --lsd <MM/DD/YYYY> reporting flags.
• Documents the new history tracking behavior in the README.
• Includes two small build compatibility fixes needed for newer Linux toolchains: converts Beast header values without .to_string() and includes <cstdint> where std::uint16_t is used.

Validation:

• git diff --check HEAD~1 HEAD
• WSL full build from dooked/:
  • cmake .
  • make -j2
• Smoke test:
  • ./dooked --help

Bounty payout:

• PayPal payout details can be provided privately by DM if this PR is selected and merged.

[jdjioe5-cpu]

Update: I fixed the local WSL build blockers as well. The branch now builds successfully with cmake . && make -j2, and ./dooked --help shows the new --fs, --ls, and --lsd flags.