docs: add Javadoc to config store interfaces (batch 1 of 2)

[ginccc]

Summary

Most store interfaces in configs/ lack Javadoc. They follow a consistent CRUD pattern and can be documented by reading the implementation class.

Interfaces to document (8)

• src/main/java/ai/labs/eddi/configs/agents/IAgentStore.java
• src/main/java/ai/labs/eddi/configs/apicalls/IApiCallsStore.java
• src/main/java/ai/labs/eddi/configs/llm/ILlmStore.java
• src/main/java/ai/labs/eddi/configs/mcpcalls/IMcpCallsStore.java
• src/main/java/ai/labs/eddi/configs/output/IOutputStore.java
• src/main/java/ai/labs/eddi/configs/parser/IParserStore.java
• src/main/java/ai/labs/eddi/configs/rules/IRuleSetStore.java
• src/main/java/ai/labs/eddi/configs/dictionary/IDictionaryStore.java

How to write good Javadoc

1. Read the implementation class to understand what the interface does
2. Look at the model class it operates on
3. Write 2-3 lines: purpose + what consumes it + key behaviors

Good example (see IConversationMemoryStore):

/**
 * Persistence store for conversation memory snapshots.
 * Called by the lifecycle pipeline to save/load conversation state
 * between turns and across server restarts.
 */

Bad example (don't do this):

/** Store for agents. */

Note: If the interface currently has only /** @author ginccc */, replace it with
meaningful Javadoc. Per CONTRIBUTING.md, @author tags are not used in new code.

Acceptance criteria

• All 8 interfaces have class-level Javadoc (2+ meaningful lines)
• Any existing @author tags are removed
• ./mvnw compile passes