v0.18.0 — Phase 8 — Multi-workspace federation registry

Phase 8 — Multi-workspace federation registry

Closes the substrate-completion-arc Phase 8 backlog item: introduces an opt-in
host-level registry (~/.broomva/global/registry.yaml) that catalogues every
bstack-governed workspace on this machine, plus a bstack status --aggregate
rollup that walks the registry and surfaces cross-workspace composite-ω.
Federation is read-only aggregation — each workspace remains the source
of truth for its own state; the registry is the index, not the database.

This release lands on top of v0.16.0 (multi-layer RCS closure) and v0.17.0
(BROOMVA_ROOT convention). Together they form the substrate that PR2
(v0.19.0, BRO-48 — Closure Contract) generalizes from 4 hard-coded RCS layers
to N user-declared domain arcs.

New scripts + bin (3)

• NEW bin/bstack-workspace — 90-line bash dispatcher delegating to
  scripts/workspace.py. Subcommands register | list | info | deregister
  with --json + --tag + per-subcommand --path/--name filters. Exit
  codes documented in the help block: 0 ok, 2 invalid args, 3 schema/parse
  error, 4 target not found, 5 name conflict at different path.
• NEW scripts/workspace.py — 523-line Python registry manager with an
  inline minimal-YAML parser fallback (when PyYAML is absent), atomic
  writes (.tmp + replace), and schema-version checking. Honors
  BSTACK_REGISTRY env (default ~/.broomva/global/registry.yaml) and
  BSTACK_DIR for VERSION detection. SLO: register/list p50 < 100ms.
• NEW schemas/workspaces.v1.json — JSON-schema draft-07 contract for
  the registry. schema_version: 1 is the only valid value at v0.18.0;
  field bstack_version matches ^[0-9]+\.[0-9]+\.[0-9]+(-[A-Za-z0-9.-]+)?$;
  name matches ^[A-Za-z0-9][A-Za-z0-9._-]*$ (1–64 chars).

New tests (1)

• NEW tests/workspace.test.sh — 203-line hermetic bash suite, 10 cases:
  fresh register, refresh on same path, name conflict at different path (exit
  5), info --path reports registered: true, deregister by path, deregister
  miss (exit 4), schema_version=99 → exit 3, tag accumulation on refresh,
  invalid name (exit 2), --help block renders. Every test uses
  BSTACK_REGISTRY=$(mktemp) so the host registry is untouched. All 10 GREEN.

Changed (4)

• CHANGED bin/bstack — dispatcher: new workspace) exec "$BIN_DIR/bstack-workspace" "$@" case + Federation: usage section
  • status --aggregate cross-reference under Observability.
• CHANGED bin/bstack-status — adds --aggregate (alias
  --multi-workspace) flag. Reads the registry via bash bin/bstack-workspace list --json, then for each entry attempts bash <path>/bstack/scripts/compute-budget-status.sh --json
  (falls back to reading <path>/.control/audit/composite-omega.jsonl),
  emits a table: name × bstack_version × composite_ω × last_seen × verdict.
  JSON form via --json --aggregate. Read-only, no writes anywhere.
• CHANGED scripts/doctor.sh — adds §20 (Workspace federation registry):
  informational when no registry present (federation opt-in); hard gap on
  schema mismatch (schema_version != 1); soft warning on entries with
  last_seen_at > 30 days. Reads BSTACK_REGISTRY env or default path.
• CHANGED assets/templates/{SKILL,AGENTS,CLAUDE}.md.template — light
  surface updates so freshly-bootstrapped workspaces document the
  bstack workspace commands. Federation is not a new primitive (no
  P21); it composes existing primitives (Snapshot P15 + multi-layer ω
  from v0.16.0 §19).

Doctor section table after this release

§	Title	Source	Hard gap when
§14	RCS stability budget	compute-lambda.sh	any λᵢ ≤ 0
§15	L3 stability gate-flow wiring	install-l3-stability.sh	(informational only)
§16	L0 plant audit	l0-tools.jsonl	>10000 events runaway
§17	L1 autonomic reflex compliance	l1-reflexes.jsonl	compliance < 30%
§18	L2 EGRI promotion throttle	l2-promotions.jsonl	over τ_a₂ budget
§19	Multi-layer composite health	compute-budget-status.sh	any layer unstable
§20	Workspace federation registry	bin/bstack-workspace list	schema_version != 1

Test plan executed

• bash -n syntax check across all new + modified scripts → clean.
• bash bin/bstack-workspace --help → renders subcommand block.
• BSTACK_REGISTRY=/tmp/test.yaml bash bin/bstack-workspace register --path /tmp --name test --json
  → exit 0, action: registered.
• BSTACK_REGISTRY=/tmp/test.yaml bash bin/bstack-workspace list --json → count: 1.
• BSTACK_REGISTRY=/tmp/test.yaml bash bin/bstack-workspace deregister --name test --json
  → exit 0, count: 0.
• bash tests/workspace.test.sh → 10/10 GREEN.
• bash scripts/doctor.sh against worktree → 87/90 passed (baseline; §20
  fires as informational with no registry — same total).
• bash scripts/compute-budget-status.sh --human against ~/broomva
  → composite still stable.

Honest scope caveats

• Federation is local-filesystem only. No network/IPC transport. A
  workspace on a remote host has to register itself locally; cross-host
  rollup is deferred.
• The registry is read-only aggregation. bstack status --aggregate does
  not mutate any registered workspace's state. CRDT-replicated cross-workspace
  promotion (the swarm-autoresearch-loop primitive) is a future Phase 8.5
  spec, not in this release.
• last_seen_at is updated on register (which is also "refresh"); it is
  not automatically updated by --aggregate. A future hook may bump
  last_seen_at on every successful compute-budget-status.sh invocation
  per workspace.

Spec doc + cross-references

• Linear ticket: BRO-47
• Prior release: v0.17.0 (BROOMVA_ROOT convention, #47, BRO-1223 follow-up)
• Next release: v0.19.0 (Closure Contract — arcs.yaml + composite-ω drift trend,
  BRO-48) builds on this substrate.
• Concept entity: research/entities/concept/closure-contract.md (in broomva
  workspace) — captures the 5-tuple generalization Phase 8 helps enable.