docs(adr): support-service → IIOS naming migration (ADR-0001)

Establishes a docs/adr convention and records the naming-migration decision:
interaction-centric Iios-prefixed vocabulary as canonical, support as a
namespaced specialization (KG-16), @insignia/iios-* package scope, and a
greenfield-and-deprecate (strangler) migration off the legacy support-service.
Includes the legacy→IIOS naming map.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

docs/adr/README.md

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+# Architecture Decision Records (ADRs)
+
+This directory records the significant, hard-to-reverse decisions behind IIOS —
+the *why*, not just the *what*. Code shows what we did; ADRs explain the choice so a
+future contributor doesn't relitigate it or unknowingly violate it.
+
+## Convention
+
+- One file per decision: `NNNN-kebab-title.md` (zero-padded, monotonically increasing).
+- Each ADR has: **Status**, **Context**, **Decision**, **Consequences**, and (where useful)
+  **Alternatives considered**.
+- Status is one of `Proposed` · `Accepted` · `Superseded by ADR-XXXX` · `Deprecated`.
+- ADRs are immutable once `Accepted`. To change a decision, write a new ADR that supersedes it.
+
+## Index
+
+| ADR | Title | Status |
+|-----|-------|--------|
+| [0001](0001-support-service-to-iios-naming-migration.md) | `support-service` → IIOS naming migration | Accepted |