Add AgentEvolution haystack ServiceType (Phase 2)

[AlexMikhalev]

Summary

Add AgentEvolution as a new ServiceType in the haystack architecture, enabling agents to search their prior lessons and memories as part of domain knowledge retrieval.

Approach

• Add AgentEvolution variant to ServiceType enum in crates/terraphim_config/src/lib.rs
• Implement IndexMiddleware that searches persisted LessonsState and MemoryState, returns matching entries as Document
• Add match arm in search_haystacks() for the new service type
• Add knowledge_haystacks and max_knowledge_items to AgentDefinition config
• Extend spawn_agent() to search haystacks with task as needle, prepend results to prompt

TOML Config Example

[[agents]]
name = "product-development"
max_knowledge_items = 5

[[agents.knowledge_haystacks]]
location = "product-development"
service = "AgentEvolution"

[[agents.knowledge_haystacks]]
location = "~/.config/terraphim/kg/projects/terraphim-ai/"
service = "Ripgrep"

Critical Files

• crates/terraphim_config/src/lib.rs:273 -- ServiceType enum
• New: crates/terraphim_middleware/src/haystack/agent_evolution.rs -- IndexMiddleware impl
• crates/terraphim_middleware/src/indexer/mod.rs -- search_haystacks() match arm
• crates/terraphim_orchestrator/src/config.rs -- AgentDefinition fields
• crates/terraphim_orchestrator/src/lib.rs -- spawn_agent() enrichment

Acceptance Criteria

• Agent with configured knowledge_haystacks receives prior lessons in prompt
• Empty haystack returns gracefully
• TOML config parses correctly
• cargo test --workspace passes

Dependencies

• Blocked by: Phase 1 (agent output persistence)
• Related: feat: Add context-hub haystack connector #651 (context-hub haystack), Gitea yarn.lock commited #81, Remove build artifacts #79