docs: add module documentation in AsciiDoc with PlantUML diagrams

Generated by per-group subagents covering all 52 modules across:
core (18), infrastructure (10), apps (5), interfaces (3),
plugins (7), testing (9)

Documentation format:
- AsciiDoc (.adoc) files in docs/modules/<group>/
- PlantUML (.puml) files in docs/diagrams/
- .adoc files reference diagrams via include:: directives

Each doc covers: purpose, responsibilities, non-responsibilities,
key types, event flow, integration points, invariants, PlantUML
diagram, known issues, and open questions.

docs/diagrams/core-inference.puml

@@ -0,0 +1,73 @@
+@startuml
+interface InferenceProvider
+interface ProviderRegistry
+interface InferenceRouter
+interface RoutingStrategy
+interface InferenceCancellationToken
+interface Tokenizer
+interface InferenceReducer
+interface Projection
+
+class DefaultInferenceRouter
+class DefaultInferenceReducer
+class InferenceProjector
+class InferenceRepository
+
+class InferenceRequest
+class InferenceResponse
+class InferenceState
+class InferenceRecord
+class GenerationConfig
+class ToolCallRequest
+class ToolDefinition
+class ModelCapability
+class CapabilityScore
+class ProviderHealth
+class FinishReason
+class ResponseFormat
+
+enum InferenceStatus
+
+InferenceRouter <|.. DefaultInferenceRouter
+RoutingStrategy <|-- (DefaultInferenceRouter uses)
+InferenceProvider <|-- (DefaultInferenceRouter uses)
+ProviderRegistry <|-- (DefaultInferenceRouter uses)
+InferenceReducer <|.. DefaultInferenceReducer
+Projection <|.. InferenceProjector
+InferenceProjector --> InferenceReducer
+InferenceRepository --> InferenceProjector
+
+DefaultInferenceRouter --> RoutingStrategy
+DefaultInferenceRouter --> ProviderRegistry
+InferenceRequest --> GenerationConfig
+InferenceRequest --> "contextPack" ContextPack
+InferenceRequest --> "tools" ToolDefinition
+InferenceResponse --> "toolCalls" ToolCallRequest
+InferenceResponse --> FinishReason
+InferenceProvider --> Tokenizer
+InferenceRecord --> InferenceStatus
+
+package "core:events" <<External>> {
+  [InferenceStartedEvent]
+  [InferenceCompletedEvent]
+  [InferenceFailedEvent]
+  [InferenceTimeoutEvent]
+}
+package "core:context" <<External>> {
+  [ContextPack]
+}
+package "core:artifacts" <<External>> {
+  [JsonSchema]
+}
+package "core:sessions" <<External>> {
+  [Projection]
+  [EventReplayer]
+}
+
+DefaultInferenceReducer ..> "core:events"
+InferenceRepository ..> "core:events"
+InferenceRepository ..> "core:sessions"
+InferenceRequest ..> "core:context"
+ResponseFormat.Json ..> "core:artifacts"
+
+@enduml