feat: Add incremental conversation persistence for live visibility during agent loops

[vinodvx]

Description

Adds EnableConversationSaveOnIteration to flush conversation messages after each tool round (not only at run end), so Redis/UI can observe progress while a multi-step run is still in flight.

Changes

• Config: EnableConversationSaveOnIteration() on agent/worker; wired through AgentExecution.Session
• Local runtime: conversationMemoryEnabled guard; persistedMessageCount saves only new messages (no duplicate history writes, no mid-run refetch)
• Temporal runtime: per-iteration save + workflow clear; end-of-run saves remainder; same guard on fetch/persist paths
• Examples infra: Redis in docker-compose.yml; infra:redis:up/down in Taskfile and infra:deps
• agent_with_conversation: Redis store (REDIS_ADDR), optional incremental save in example
• Docs: README conversation section, examples README (Redis + env vars)

Test plan

• go test ./internal/runtime/local/... ./internal/runtime/temporal/...
• task infra:redis:up then go run ./agent_with_conversation (multi-turn)
• Temporal worker with EnableConversationSaveOnIteration — verify Redis updates between tool rounds

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update
• Refactor / chore

Related issues

Closes #26

Checklist

• I have run make check
• I have run task examples:all
• I have run make tidy if I added or removed dependencies
• Commit messages follow conventional commits (e.g. feat:, fix:, docs:)
• I have added/updated tests for my changes
• Documentation is updated if needed

[codecov]

Codecov Report

❌ Patch coverage is 29.26829% with 29 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
internal/runtime/temporal/agent_workflow.go	14.28%	15 Missing and 3 partials ⚠️
internal/runtime/local/agent_loop.go	40.00%	7 Missing and 2 partials ⚠️
pkg/agent/config.go	60.00%	2 Missing ⚠️

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