arinc429-bus-loadinglisted

# ARINC 429 Bus Loading (avionics/data-bus/arinc429-bus-loading) Use when the task is budgeting an ARINC 429 transmit schedule for a civil avionics data bus: how many words per second the label rate table asks the transmitter to send, what that costs in bus occupancy, and whether the schedule fits the link with headroom. Every transmitted ARINC 429 word occupies 36 bit-times on the bus, 32 data bits plus the 4-bit gap between words, so a schedule of label rates sums into a total word rate and the word rate prices the bus directly at 36 bits per word. The module is pure Python stdlib and deterministic; you supply the label rate schedule (a list of rates in labels per second, or a dict mapping a label to its rate) and it returns the load, utilization, capacity verdict and design headroom. It pairs with avionics/data-bus/arinc429-protocol, which covers the 32-bit word layout and parameter coding itself (this leaf never builds or interprets a word), and with avionics/data-bus/arinc664-afdx and mil-std-1553 for the other civil and military bus loading models. ## Domain quick reference - Every ARINC 429 word occupies BITS_PER_WORD = 36.0 bit-times (32 data bits plus a 4-bit gap), whatever the label content, so the word rate alone determines bus occupancy. - Total word rate: total_word_rate(label_rates) = sum of the per-label rates. A schedule of 3 labels at 50 Hz, 4 at 20 Hz and 2 at 10 Hz totals 3*50 + 4*20 + 2*10 = 250 words/s. - Bus load: bus_load_bps(words_per_s) = w