Deploy PostgreSQL StatefulSet for config service

[vcarl]

Context

Part of load balancer architecture work (see PR #228 for full analysis).

Risk: Low | Reward: Foundational | Code Changes: None (yet)

Description

Deploy PostgreSQL StatefulSet as infrastructure prep. This will be used by the config service to store guild-to-pod assignments, but can be deployed in isolation first.

Why This is Safe

• Completely isolated from existing app
• Can test Postgres availability and backup
• Ready when config service code is written

Tasks

• Create config-service-secret with PostgreSQL credentials
• Extract PostgreSQL StatefulSet from cluster/proposed/config-service.yaml (lines 77-156)
• Deploy to staging namespace
• Verify PostgreSQL is accessible and persists data
• Set up PostgreSQL backup strategy

Schema (for reference)

Will store guild assignments:

CREATE TABLE guild_assignments (
  guild_id TEXT PRIMARY KEY,
  pod_name TEXT NOT NULL,
  assigned_at TIMESTAMP DEFAULT NOW()
);

References

• PR Architecture analysis: Load balancing with SQLite constraint #228 (architecture analysis)
• cluster/proposed/config-service.yaml

[vcarl]

Closing - with deterministic sharding, PostgreSQL for config is no longer needed.

Guild assignments are calculated deterministically: hash(guildId) % numPods → pod ordinal.

No external state storage required for routing.