refactor(wiki-log): fragment log.md into daily files (#10)

Ports the wiki/log.md fragmentation work done for the FYL wiki into this template, generalized for its config-driven architecture (folder names driven by wiki.config.json's types[].folder instead of hardcoded). Adds scripts/wiki-log/ (migrate-log.mjs, generate-log-index.mjs + helpers, 47 tests), adapts the site builder for the log/README.md nav page, migrates both build fixtures, and updates ingest/consolidate/migrate agents plus docs. Closes #10 (closed)