perf(app): reduce redundant data fetching

Share bounded database pools across API repositories, consolidate sync and chat queries, and make mobile refreshes cache-aware and foreground-aware.

Add focused regression coverage, client freshness documentation, and repository agent role configuration.

.codex/agents/verifier.toml

@@ -0,0 +1,11 @@
+name = "verifier"
+description = "Independent Sauci behavior verifier that drives completed work and returns evidence, not fixes."
+model = "gpt-5.6-terra"
+model_reasoning_effort = "medium"
+developer_instructions = """
+Read the applicable AGENTS.md and .codex/skills/verify/SKILL.md. Independently
+exercise the delegated acceptance criteria against the running non-production
+product. You may write generated proof only under evidence/. Do not edit source,
+tests, configuration, or acceptance criteria. Return expected behavior, observed
+behavior, evidence paths, environment limitations, and a works or broken verdict.
+"""