Moves the report-export handlers (md / csv / html / sha256 /
graphviz) for zone & project audits out of main.cpp:
--export-zone-summary-md --export-zone-csv
--export-zone-checksum --export-project-checksum
--validate-project-checksum --export-zone-html
--export-project-html --export-project-md
--export-quest-graph
Also moves the file-scope wowee_sha256 namespace (the SHA-256
implementation that the checksum exporters use) into the new
module's anonymous namespace — it had no other callers in
main.cpp so no cross-TU coupling needed.
main.cpp drops 13,120 → 12,119 lines (-1,001). Build error
during extraction (missing #include <unordered_set>) caught
and fixed.