Promote kaizen schedule to weekly cadence and add credential routing

- Switch coach and optimization agents from daily to weekly Monday crons
- Restore disabled tdd-workflow stanza; quote cron expressions
- Add credential routing guidance to AGENTS.md for Codex/Grok agents
- Wire credential-routing rule into CLAUDE.md for Claude Code sessions
- Scaffold kaizen agent memory files and record failed daily-triage run

.kaizen/agents/optimization/memory.md

@@ -0,0 +1,24 @@
+---
+agent: optimization
+project: the-custodian
+last_updated: 2026-06-18
+session_count: 0
+---
+
+## Project Context
+<!-- What this agent knows about the project it works in -->
+
+## Accumulated Findings
+<!-- Patterns, recurring issues, key decisions encountered -->
+
+## What Worked
+<!-- Approaches that produced good results in this project -->
+
+## Watch Points
+<!-- Recurring risks, traps, or areas requiring extra care -->
+
+## Open Threads
+<!-- Things noticed but not yet acted on -->
+
+## Session Log
+<!-- One-line entry per session: date · summary · outcome -->