Architecture decisions

Decisions that shape MEME and are not derivable from the code alone are recorded here as lightweight architecture decision records (ADRs). Each record states the context, the decision and its consequences, so a later reader knows why the service looks the way it does before proposing to change it.

ADR	Decision	Status
0001	MEME is one dependency-free Go binary; the solvers are external Python processes	accepted
0002	Validation is capability-gated: nothing a payload asks for is dropped without an error or a warning	accepted
0003	Framework-only concepts travel in per-target native blocks, never in the canonical schema	accepted
0004	Golden files and a validation matrix freeze the emitter contract	accepted
0005	Simulation is an asynchronous job with a zipped result bundle	accepted
0006	Framework versions are separate targets: a default, version variants and aliases	accepted
0007	The environment ships free solvers only: HiGHS, CBC and GLPK	accepted
0008	Power flow is a PyPSA run mode over an electrical network in the canonical model; MEME never chains jobs	accepted (amended by 0009)
0009	Reactive power, voltage control, shunts and fixed transfers complete the power-flow network; power-flow inputs are ignored where no power flow runs	accepted
0010	The electrical network enters the optimization: linear power flow, line expansion, security constraints and transmission economics	accepted
0011	PyPSA optimization completeness: Store-based storage, modular capacity, retirement, slack demand, copperplate, unit-commitment extras and multi-period investment	accepted

Adding a record

Copy 0000-template.md to the next free number, fill it in, add a row above, and link it from the pull request. A record is never rewritten once accepted: a factual detail that has aged is corrected in a dated Amendments section at the end of the record (and the status notes it), and a decision that changes gets a new number and marks the old one superseded.