Task: Write the four synthetic journeys

Four journey documents stand in the market data group beside the six synthetic prototypes, each with a wireframe, a coverage table and its gaps.

• Each journey carries the sections the extraction standard requires, with the coverage table naming the synthetic subject each step reaches and its status.
• Every one of the six synthetic prototypes is named under a journey's * Prototype section, or its absence is stated.
• The market data group hub lists the new journeys, and org-links and the journey checks pass.

(Implementation strategy. Written when work starts; key decisions are distilled into the parent story's * Decisions at close, but the plan itself stays — it is the historical record of what we did.)

Every number this task claims about a tree, with the command that produced it and the commit it was measured at. A number without both is not a measurement, because a clean-up record describes a tree and trunk moves under a branch: a consumer count, a gate's component count and a suite's size all change with no code changing, and the reader of a bare number cannot tell which tree it came from. Where the raw output matters, put it in an evidence/ file beside the task and name that file in the Command column.

Manual QA scenarios (scaffolded via compass add test_scenario) that verify this task. Link new ones here as they're created; the scenario doc itself links back via its "Verifies task" field.

Four journeys now stand beside the six synthetic prototypes, which had no journey at all before this:

• Author an FX price feed — the pair, the process, the mixture of Gaussians and the sample paths, with the across-feeds component view the mixture is browsed from.
• Author an IR curve feed — the currency, index and role, the short-rate process and its parameter values, and the tenor ladder the curve is bootstrapped from.
• Run a synthetic collection — the feeds a collection owns, what it covers and what is running, and the one folder-scoped start.
• Manage the yield curve process types — the models and their parameters kept as data, so a new model appears in the curve editor with no change to it.

Every subject in the four coverage tables was verified against the protocol headers rather than assumed, and the gaps are stated rather than smoothed over. The FX feed has no subject that lists the vintages a price source offers, so the step is marked missing; two IR reads and the process-type lists carry an id_one_of filter where the screen needs the parent or an order, so those are partial; and the collection's gaps — no coverage read, an unscoped global running set, skipped feeds returned as counts only — are named.

The journeys link their prototypes' design notes by id, which is why the prototype sweep had to land first.