docs: consolidate learning_ai_smart_auth references into learning_ai_auth_app
The smart_auth docs-only repo has been merged into learning_ai_auth_app.
Updates all cross-repo references:
- adoption/learning_ai_smart_auth.md merged into adoption/learning_ai_auth_app.md
- WORKSPACE_INVENTORY: combined row (now 13 active repos, was 14)
- CODING_AGENT_AUTOMATION_PLAYBOOK: combined row, dropped from for-loop
- GITEA_LOCAL_CI: removed from no-CI list
- ECOSYSTEM_APPROVALS_AND_TRUST_MODEL: ref input consolidated
- ECOSYSTEM_CROSS_POLLINATION_OPPORTUNITIES: capability map + per-repo section consolidated
- repos.txt, run-code-review.md, refresh-chat-history.md, update-agent-docs.sh: drop smart_auth
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