11-technical-debt: comprehensive debt enumeration

New document for the hackathon's recurring question "what technical
debt exists in quicknxsv2 and mr_reduction?" Organized into 17
sections with file:line citations throughout:

  §A duplicated and parallel code (8 items)
  §B dead code and orphaned paths (4 items)
  §C hardcoded values and magic constants (7 items)
  §D load-bearing defaults (4 items)
  §E silent behavioral differences (6 items)
  §F type drift and convention inconsistency (4 items)
  §G mutable global state - Configuration class attributes (2 items)
  §H Qt widget lifecycle coupling (5 items)
  §I import-order and algorithm-registration fragility (4 items)
  §J documentation debt (7 items)
  §K version-pin and packaging conflicts (3 items)
  §L test debt (7 items)
  §M latent bugs visible in git history (13 commits tabulated)
  §N deployment and operational debt (5 items)
  §O source anomalies - typos, Py2 residue, stale comments (8 items)
  §P accidental cross-repo coupling (4 items)
  §Q priority ranking for the hackathon (Tier 1-4)

Tier-1 items total ~1 day and remove several observable numerical
discrepancies. Tier-2 items are hackathon-week scale. Tier-3 are
post-hackathon follow-ups.

Grounded in source reading of both repos at current HEAD plus Mantid
main, with git log archaeology of 13 specific commits documenting
the pattern's history.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>