Add alias propagation, if-guard enrichment, and tag-based annotations

Alias map resolves boolean combination assignments (e.g. variable_dt =
cfl_dt or cfl_adap_dt) so prohibit rules using those aliases attribute
constraints to the underlying params. If-guard enrichment adds enclosing
if-condition params (perturb_flow, down_sample, etc.) to rules within
the block. Tag-based fallback labels output flags and DEPENDENCIES info
when no other constraints exist. Coverage rises from 64% to 83%.

Fix Doxygen rendering: compound param names (bub_pp%mu_g, x_output%beg)
wrapped in backticks as a unit, snake_case identifiers backticked even
when not in registry, bare % escaped outside code spans, and % no longer
double-escaped inside backtick code spans. Fix description priority so
hand-curated DESCRIPTIONS dict takes precedence over auto-generated text.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: sbryngelson