Migrate OAuth state store from in-memory to Redis

[Copilot]

• Update StateStore interface in oauth/state_store.go to accept context.Context and return errors, update in-memory implementation accordingly
• Create Redis-backed StateStore implementation in cache/redis_oauth_state_store.go
• Update service.go to instantiate the Redis state store and update all call sites to pass ctx and handle errors
• Address code review: align default TTL fallback (1 min) with in-memory store, document why ExpiresAt is not populated (Redis TTL handles expiry)
• Apply gofmt formatting to oauth/state_store.go and cache/redis_oauth_state_store.go
• Fix Lua script to return nil instead of false for missing keys

[Copilot]

Pull request overview

Migrates OAuth state storage from an in-process sync.Map/map implementation to Redis so OAuth flows work correctly in multi-replica deployments and across restarts.

Changes:

• Updated oauth.StateStore interface to accept context.Context and return errors.
• Added a Redis-backed OAuth state store with TTL-based expiry and atomic consume semantics.
• Wired the new Redis state store into Service and updated OAuth call sites to propagate ctx and handle errors.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
internal/infrastructure/oauth/state_store.go	Extends the StateStore interface with context + error returns; adapts the in-memory store implementation.
internal/infrastructure/cache/redis_oauth_state_store.go	Introduces Redis-backed StateStore using SET with TTL and Lua GET+DEL for atomic consume.
internal/application/identra/service.go	Instantiates and uses the Redis OAuth state store (shared Redis client), updating call sites accordingly.

[Copilot]

This file isn’t gofmt-formatted (imports and block indentation lost). Please run gofmt on this file so it matches the rest of the Go codebase and avoids noisy diffs/lint failures.

[Copilot]

This new file isn’t gofmt-formatted (imports and indentation). Please run gofmt so it matches existing Redis cache implementations (e.g., redis_email_code_store.go) and keeps diffs readable.

[slhmy]

@copilot apply changes based on the comments in this thread

[Copilot]

@copilot apply changes based on the comments in this thread

Applied in 52c479d: ran gofmt on both oauth/state_store.go and cache/redis_oauth_state_store.go, and the Lua script already returns nil (not false) for missing keys.