Section 12: The Last Ticket of the Rush - Final Summary & Candidate Scorecard

Executive Summary: This closing section compresses the module into usable forms: the 60-second recap, the full D1–D12 decision ledger with every rejected alternative and flip trigger, the three traps from the overview closed with their counters, and a seven-dimension scorecard describing — in this topic's own observable behaviors — mid-level, Senior, and Staff-Principal performances — plus the isomorphs this question hides inside and a practice regimen.

The 60-Second Answer

Here is the minute that earns the hour. The ingredient is the atomic entity: a preset salad is a recipe over ingredients, a customization is a delta from a recipe, resolution turns recipe plus delta into a concrete priced list, and an order stores that list as an immutable snapshot — so pricing, availability, nutrition, allergens, and build-your-own fall out of one model instead of becoming five special cases. Two documents ride two clocks: the 30 KB menu (v47, weekly, cached hard and versioned) and the ~1 KB availability overlay (a-312, changed hour to hour by a kitchen lead's tap). Inventory is human-grade — an audited 86 board of binary toggles, not a fictional gram ledger. Kitchen physics sets the promises: lunch demands 336 salads an hour against 120 of capacity — 2.8× — so quoted pickups come from queue depth divided by real throughput, and intake throttles honestly past the cap. Money is computed only server-side, against a named menu version, snapshotted forever.

The running example proves it end to end. Maya starts from the Harvest Cobb ($11.95), removes blue cheese, adds avocado (+$2.00), doubles the chicken (+$3.50), and the server resolves, prices, and snapshots order #1042 at $17.45 with an honest 12:32 promise. At 12:35, Marco taps 86 on avocado; within 30 seconds one tiny overlay update greys it out of every open cart and marks presets that require it "unavailable today" — while the Harvest Cobb — which never contained avocado; Maya's was a delta add — survives untouched.