Problem

crates/zeph-core/src/config/types.rs is 3331 lines — a monolithic file containing all config struct definitions. Each new feature adds more config sections, making this file increasingly hard to navigate and maintain.

Proposed Changes

Split by domain:

• config/agent.rs — AgentConfig, CompressionConfig, RoutingConfig, LearningConfig
• config/memory.rs — MemoryConfig, EmbeddingConfig, DocumentConfig, GraphConfig
• config/security.rs — SecurityConfig, TrustConfig, ExfiltrationGuardConfig, SandboxConfig
• config/providers.rs — ProviderConfig, OllamaConfig, ClaudeConfig, OpenAiConfig, GeminiConfig
• config/features.rs — Feature-gated configs (ExperimentConfig, OrchestrationConfig, SchedulerConfig)
• config/logging.rs — LoggingConfig, LogRotation
• config/ui.rs — TuiConfig, SubAgentConfig

Re-export all types from config/mod.rs to preserve the public API.

Acceptance Criteria

• No file in config/ exceeds 500 lines
• All re-exports preserved in config/mod.rs
• All tests pass unchanged
• No change to serialized TOML format

Files

• crates/zeph-core/src/config/types.rs (3331 lines)
• crates/zeph-core/src/config/mod.rs