Fix raw LaTeX artifacts in all HTML papers for proper KaTeX rendering

- agent-scheduler: 91 math span replacements (display/inline math, entities)
- planner-engine: ~35 replacements (equations, align blocks, inline math)
- synthesis: 50+ replacements (equations, inline math, HTML entities in math)
- memory-layer, tool-interface: already clean, no changes needed

Converted <span class="math display/inline"> to $$/$$ delimiters,
\begin{align} to \begin{aligned}, fixed &middot;/&times; in math contexts.

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

Author: MagnetonIO