docs(backend): correct stale 'msb from Phase 2' framing; msb is the default (#307)

docs/repository-ecosystem.md

@@ -198,8 +198,8 @@ If you find patterns diverging between repos:
 ## Cross-Repo Multi-Workspace Patterns
 
 When working with multiple repositories simultaneously, you can mount them into a single sandbox
-using Docker's `sbx` CLI. This enables workflows where an agent can reference one repo while
-editing another.
+via `acq` (the sandboxing wrapper). This enables
+workflows where an agent can reference one repo while editing another.
 
 ### Common Cross-Repo Modes
 
@@ -212,13 +212,14 @@ editing another.
 
 ### Repository Ownership
 
-- **Quickstart** owns the detailed `sbx` CLI setup instructions
+- **Quickstart** owns the detailed `acq` setup instructions
 - **Patterns** provides high-level guidance on when to use cross-repo workflows
 - **Playbook** defines standards that may be referenced from other repos
 
-For `sbx` command syntax and examples, see the
-[Multiple Workspaces](https://github.com/GSA-TTS/agentic-coding-quickstart/blob/main/docs/QUICKSTART_SBX.md#multiple-workspaces)
-section in the quickstart guide.
+For command syntax and examples, see the quickstart guide's
+[Quick Start](https://github.com/GSA-TTS/agentic-coding-quickstart/blob/main/docs/QUICKSTART.md)
+and its [Multiple Workspaces](https://github.com/GSA-TTS/agentic-coding-quickstart/blob/main/docs/QUICKSTART_SBX.md#multiple-workspaces)
+section.
 
 ### Security Best Practice
 

integrations/isolation/acq-kits/README.md

@@ -4,8 +4,7 @@ Neutral, backend-agnostic **mixin kits** for
 [`acq`](https://github.com/GSA-TTS/agentic-coding-quickstart) — the pluggable
 isolation-backend wrapper. A kit configures an agentic-coding sandbox
 declaratively (network egress, files to drop, lifecycle commands, agent
-context); `acq` translates the neutral spec into whichever backend is active
-(`sbx` today; `msb` from Phase 2; `ppp` later).
+context); `acq` translates the neutral spec into whichever backend is active.
 
 These are isolation/environment building blocks — they configure the *sandbox*,
 not agent behavior. (Behavioral patterns live in `skills/`, `prompts/`, etc.)

integrations/isolation/acq-kits/agentic-coding-playbook/README.md

@@ -6,8 +6,7 @@ kit** that delivers the GSA
 the federal `AGENTS.md` rules and the Agent Skills — into a sandbox.
 
 > **Neutral (backend-agnostic) kit.** This is the `schemaVersion: "hybrid/v1"`
-> form consumed by `acq`, which selects an isolation backend (`sbx` today; `msb`
-> from Phase 2). It replaces the former `sbx-kits/playbook-kit/` sbx-only spec.
+> form consumed by `acq`, which abstracts the isolation backend. It replaces the former `sbx-kits/playbook-kit/` sbx-only spec.
 > See [backend parity](#backend-parity) and
 > [`../../docs/decisions/0001-neutral-hybrid-v1-acq-kits.md`](../../docs/decisions/0001-neutral-hybrid-v1-acq-kits.md).
 

integrations/isolation/acq-kits/git-ssh-sign/README.md

@@ -9,8 +9,7 @@ Your **private key never leaves the host** — the sandbox forwards the SSH agen
 and signing resolves the public key from that agent at signing time.
 
 > **Neutral (backend-agnostic) kit.** This is the `schemaVersion: "hybrid/v1"`
-> form consumed by `acq`, which selects an isolation backend (`sbx` today; `msb`
-> from Phase 2). It replaces the former `sbx-kits/git-ssh-sign/` sbx-only spec.
+> form consumed by `acq`, which abstracts the isolation backend. It replaces the former `sbx-kits/git-ssh-sign/` sbx-only spec.
 > See [backend parity](#backend-parity) and
 > [`../../docs/decisions/0001-neutral-hybrid-v1-acq-kits.md`](../../docs/decisions/0001-neutral-hybrid-v1-acq-kits.md).
 >

integrations/isolation/acq-kits/kits.yaml

@@ -2,10 +2,10 @@
 #
 # Maps each neutral (schemaVersion: "hybrid/v1") kit to the backends that
 # support it and a prose parity note describing any per-backend capability
-# difference. For Phase 2 the supported backends are sbx and msb; ppp arrives in
-# Phase 3. Parity is ADVISORY (documented, not machine-enforced) — the source of
-# truth for a per-backend difference is the kit's spec.yaml backend_shortcuts and
-# its README parity note.
+# difference. `acq` abstracts the isolation backend; the authoritative backend
+# set lives in the acq wrapper, not here. Parity is ADVISORY (documented, not
+# machine-enforced) — the source of truth for a per-backend difference is the
+# kit's spec.yaml backend_shortcuts and its README parity note.
 #
 # See integrations/isolation/docs/decisions/0001-neutral-hybrid-v1-acq-kits.md.
 schemaVersion: "acq-kits-registry/v1"

integrations/isolation/acq-kits/usai-provider/README.md

@@ -5,8 +5,7 @@ kit** that configures a coding agent to use the GSA **USAi** OpenAI-compatible
 endpoint as its model provider, with network egress allow-listed.
 
 > **Neutral (backend-agnostic) kit.** This is the `schemaVersion: "hybrid/v1"`
-> form consumed by `acq`, which selects an isolation backend (`sbx` today; `msb`
-> from Phase 2). It replaces the former `sbx-kits/usai-provider-kit/` sbx-only
+> form consumed by `acq`, which abstracts the isolation backend. It replaces the former `sbx-kits/usai-provider-kit/` sbx-only
 > spec. See the [backend parity](#backend-parity) note and
 > [`../../docs/decisions/0001-neutral-hybrid-v1-acq-kits.md`](../../docs/decisions/0001-neutral-hybrid-v1-acq-kits.md).
 

integrations/isolation/acq-kits/zscaler-ca-certificate/README.md

@@ -7,8 +7,7 @@ HTTPS-inspecting proxy — so outbound HTTPS works on networks where Zscaler
 intercepts and re-signs TLS traffic.
 
 > **Neutral (backend-agnostic) kit.** This is the `schemaVersion: "hybrid/v1"`
-> form consumed by `acq`, which selects an isolation backend (`sbx` today; `msb`
-> from Phase 2). It replaces the former `sbx-kits/zscaler-ca-certificate/`
+> form consumed by `acq`, which abstracts the isolation backend. It replaces the former `sbx-kits/zscaler-ca-certificate/`
 > sbx-only spec. See [backend parity](#backend-parity) and
 > [`../../docs/decisions/0001-neutral-hybrid-v1-acq-kits.md`](../../docs/decisions/0001-neutral-hybrid-v1-acq-kits.md).