% journal.tex — top-level document that aggregates all dated entries.
%
% Build:
%   cd journal && latexmk -pdf journal.tex
% or individual entry:
%   cd journal && latexmk -pdf entries/2026-04-17-controllers-linear-reach.tex

\input{preamble.tex}

\title{HAHACS Lab Journal\\
       \large PWR\_HYBRID\_3 preliminary example, invention log}
\author{Dane Sabo, with Claude (Hacker-Split)}
\date{Started \today}

\begin{document}

\maketitle
\tableofcontents
\newpage

\section*{How to read this journal}

Each section is a dated session.  Sessions are written in two styles:

\begin{itemize}
  \item \textbf{Deep (A-style)}: full invention-log depth.  Derivations
        in math, code snippets with commentary, figures with long
        captions, dead-ends documented, terminal output included where
        it changes the story.  A reader in 2030 should be able to
        rebuild the work from this alone.
  \item \textbf{Narrative (B-style)}: end-of-session notes with
        pointers.  Marked with \apass{some detail} callouts for
        content that should be expanded in a later A-pass.
\end{itemize}

\textbf{File-path archaeology note.}  Entries dated on or before
2026-04-20 (afternoon) refer to MATLAB files under \texttt{plant-model/}
and a MATLAB-Julia split where Julia code lived under \texttt{julia-port/}.
The 2026-04-20 evening mega-session ported everything to Julia and
deleted MATLAB; the result is the unified \texttt{code/} directory.
Path references in earlier entries are historically accurate for their
date; recover the corresponding sources via \texttt{git log} or the
parent commit at the time.

Callout boxes signal specific content types:

\begin{derivation}
Mathematical derivations — algebra, integrals, limits.  Where they
matter to the safety claim, they live here in full.
\end{derivation}

\begin{decision}
Design decisions made during the session, with the rationale and the
alternatives considered.
\end{decision}

\begin{deadend}
Approaches that didn't work and why.  These are as valuable as the
working paths — they keep the next explorer from repeating the mistake.
\end{deadend}

\begin{limitation}
Known-approximate or known-broken behavior.  Soundness gaps live here.
Each limitation ties to a plan or an open question.
\end{limitation}

\newpage

% ---- Session entries, in chronological order -------------------------------
\input{entries/2026-04-17-controllers-linear-reach.tex}
\newpage
\input{entries/2026-04-20-predicates-boundaries-julia-nonlinear.tex}
\newpage
\input{entries/2026-04-20-evening-mega-session.tex}
\newpage
\input{entries/2026-04-20-overnight-prompt-jump.tex}

\end{document}