test: give every ignored workflow an executed integration lane

[jBernavaPrah]

Purpose

Third step of the accepted test-boundary refactor: selecting a suite now establishes its prerequisites. No test is silently skipped, no test hides behind an environment early-return, and no feature flag gates a lane — every formerly ignored workflow runs in a job that builds what it needs.

What changes

• Composition legs (tests/contracts/robot): #[ignore] removed; PHOXAL_EVAL_BUNDLE and PHOXAL_SUBSTITUTION_BUNDLE are required parameters, built by the new integration acceptance job. The substitution run uses the checked-in robot.substitution.yaml (selects encoder-b for consumer.encoder) instead of a hand-edited manifest.
• Warm-edit regression (tests/contracts/standard-plus-custom): #[ignore] and its environment gate removed; the job selection replaces lane selection because the scratch package builds its own cold dependency tree.
• Host acquisition: the two paths move from phoxal-build's build_api suite into a dedicated tests/host-acquisition fixture package (phoxal-host-acquisition-fixture) that the integration job runs. Their stale 0.0.0-dev.7 SDK version pin (the test never ran in CI, so it drifted) becomes a manifest read that cannot drift from the framework train.
• CI: the workspace test command excludes the three prerequisite-bearing fixture packages alongside the existing supervisor and MuJoCo exclusions; the new integration acceptance job builds cargo-phoxal, the supervisor binary, and both bundles (manifest swap with restore and re-prepare), then runs the three packages. Both test jobs cache target/suites and target/tests — nested trees the Rust cache does not cover — keyed on the lockfile.
• Nested build trees: prepare_cycles and prepared_selection share one target/suites/composition tree, built without incremental compilation and with line-tables-only debug info.
• consumer_policy: the exact cargo tree dependency inventories are replaced by six compilation checks for the supported consumer profiles (base, runtime, session, scenario, build, default). The profiles' dependency roles remain a manifest design property rather than something re-derived from tree output.

Verified locally, with the exact job commands

• Slimmed workspace run: 56 test binaries, 0 failures.
• Composition legs: 2/2 driving real supervisor processes (14 s).
• Warm edit: 1/1 (87 s, cold scratch build).
• Host acquisition: 2/2 through real Git and local-registry sources (283 s).
• Consumer profiles: 6/6 (43 s cold).
• clippy --workspace --all-targets -D warnings (includes the new package) and fmt --check clean.

Not yet in this PR (remaining phase-3 slice)

phoxal-build semantic tests against in-memory documents, and trybuild slimming to a representative case per guarantee.

Delivery order

Single repository; the new fixture package is publish = false; Cargo.lock records the new member only.