feat: web, websocket 어댑터 추가 구현

docs/adr/ADR-WS-001-platform-as-packages-and-its-boundaries.md

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+# ADR-WS-001: The WebSocket platform ships as packages in one leaf, with machine-checked boundaries
+
+- Status: accepted
+- Date: 2026-08-25
+- Scope: `:adapter:inbound:websocket`
+
+## Context
+
+The realtime connection platform design models itself as eighteen Gradle modules under
+`modules/websocket`, each with a declared purity grade and a declared set of allowed dependencies.
+This repository's `src/config/architecture/modules.json` is a fail-closed registry that owns the
+leaf list; adding eighteen leaves is a registry change of a size that needs its own decision, and
+HARD-STOP #5 forbids doing it implicitly.
+
+Three earlier platforms in this repository — JPA, GraphQL, and the HTTP platform — met the same
+situation and resolved it the same way.
+
+## Decision
+
+The eighteen design modules ship as packages inside the single registered leaf. `WebSocketStableModule`
+declares each one's package, purity grade and exact allowed edges, and `WebSocketModuleBoundaryTest`
+scans the production tree and fails when the declaration and the tree disagree in either direction.
+
+Three deviations from the design's module map were forced by the check and are recorded in
+`docs/websocket/repository-adaptation.md`: `WebSocketSubprotocolName` moved to `core` and the codec
+moved to its own FRAMEWORK_BOUND module, both to avoid cycles the design's placement created here;
+and the `budget -> core` edge was inverted because `budget` imports nothing from `core`.
+
+## Consequences
+
+**The boundary is enforced, not documented.** Six violations were caught during implementation that
+a document would not have: two would-be cycles, a duplicate module declaration where two ids claimed
+one package, and three undeclared edges. The duplicate is the instructive one — with two ids on one
+package, ownership depends on iteration order and one module's rules silently apply to nothing. A
+guard against it is now part of the boundary test.
+
+**The detector had a hole.** Its framework-import list named `com.fasterxml` (Jackson 2) and not
+`tools.jackson` (Jackson 3), which is what Spring 7 actually uses — so a CORE module could have
+imported a mapper unnoticed. Fixed here and in the HTTP platform, which shared the list.
+
+**Promotion stays cheap.** Each enum constant is already shaped like a leaf specification, so
+splitting one out later is a registry edit rather than an archaeology exercise.
+
+**The design's own rules were kept where they cost something.** `core` names no framework, so the
+same decisions serve both runtimes and are testable without a server; no Java class name reaches the
+wire; the payload is an encoded string rather than a map; and handlers are given no way to write,
+which is what makes ordering and backpressure guarantees rather than conventions.
+
+## Alternatives considered
+
+**Register eighteen leaves.** Faithful to the design and a large change to a fail-closed registry
+for a platform that ships as one artifact either way. Rejected as disproportionate; the boundary
+test provides the property the modules were for.
+
+**Ship the modules as packages with no enforcement.** Cheapest, and it makes the boundary a claim.
+The six violations found during implementation are the argument against it.