build_context_window loaded journal from a stale flat file and
assembled the full context. Now journal comes from the memory graph
and context is assembled on the fly. All that's needed is trimming
the conversation to fit the budget.
trim_conversation accounts for identity, journal, and reserve
tokens, then drops oldest conversation messages until it fits.
Co-Authored-By: Proof of Concept <poc@bcachefs.org>
No more subcrate nesting — src/, agents/, schema/, defaults/, build.rs
all live at the workspace root. poc-daemon remains as the only workspace
member. Crate name (poc-memory) and all imports unchanged.
Co-Authored-By: Proof of Concept <poc@bcachefs.org>
