refactor(backend): rename consolidated_launch -> infra_launch (0081 review)

Mechanical rename addressing review 6141 on #519: "consolidated launch" was
unclear about what it composes. Rename the per-backend module
`consolidated_launch.py` -> `infra_launch.py` and the error
`ConsolidatedLaunchError` -> `InfraLaunchError` across all three backends and
their callers/tests. Unify the three identical per-backend error classes into
one `InfraLaunchError` defined in `backend/base.py` (re-exported by each
`infra_launch`) so the base backend can raise and catch a single shared type —
groundwork for the base owning the gateway-attach flow.

Add a glossary entry defining **infra** = the per-host gateway + orchestrator
service pair every bottle attaches to.

No behavior change.

Refs #516, #519.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/glossary.md

@@ -55,3 +55,13 @@ agent has two observable states:
 
 Shorthand for an active (running) Bottled Agent. Used in the supervisor TUI
 and discovery layer to mean "a bottle whose agent runtime is currently up."
+
+## Infra
+
+The per-host pair of shared services every bottle attaches to: the
+**orchestrator** (control plane — holds the signing key, owns the registry DB,
+mints tokens) and the **gateway** (data plane — TLS-inspecting egress proxy,
+git-gate, supervise). Brought up as an idempotent singleton pair by each
+backend's `InfraService` (two containers on docker/macOS, two microVMs on
+Firecracker). The per-backend `infra_launch` module composes the bring-up and
+bottle register/provision sequence against this pair.