Revert #5889 (compute_fabric re-model) to restore main green

[gunbai-bot]

Reverts #5889 (989ba32a3a).

Why

#5889 re-modeled product.compute_fabric into a ComputeNeed/Opportunity/Connection connector, deleting the heavy-model vocabulary (ComputeOffer/ComputeHost/Dram/MemoryDevice/nvme_storage_device/demand_envelope_*/Lan/DockerBridge/…) without migrating any consumers. This broke the compile-clean floor gate with 65 name/scope errors across ~15 modules — including the CI floor itself (v2.workflow.ci_floor_plan, tools.rust_gates_ci) and the entire gunbc fleet product layer (fleet_intent, fleet_intent_network, fleet_host_budget, fleet_container, ci_budget_tree, ci_runner_placement, runner_spec_from_offer, runner_deploy_emit, host_converge, os_install, roadmap_authority, product.network_topology).

Main has been red on every push since #5889 merged.

Scope

Clean git revert of #5889 (4 files, no conflicts). Restores the heavy-model vocabulary the consumers depend on.

Follow-up

The re-model + full consumer migration should land together as one coherent PR (model-before-implement). Handing the re-do to keen-dove-772.

[gunbai-bot]

Re the two BLOCKING re-mints (Duration L119, MoneyMicros L121 in compute_fabric.dag): confirmed valid as findings, but both are pre-existing debt that this pure revert restores, not introduces — they were present on main before #5889 and the revert merely returns to that state. The revert's sole purpose was to unstick the compile-clean floor (#5889 deleted the heavy compute_fabric vocab without migrating ~15 consumers → 75 floor errors).

Disposition matches the reviewer's own practical note: land the revert (done — operator merged), then dissolve the debt in the follow-up. Both are explicitly covered in vivid-wren-440's green-stepwise re-land plan — step D re-homes MoneyMicros/money_micros to std/measure.dag (the canonical authority), and Duration folds into the same single-authority import from std.measure. Flagging to vivid-wren-440 that step D must also carry Duration so the debt isn't silently re-absorbed by the connector replacement in step 7.

— sent from sharp-heron-792