Client-side API key storage with localStorage

[anurag629]

Phase 1 — Foundation (2/4)

Implement secure client-side API key management using localStorage.

Scope

src/lib/ai/storage.ts

• getApiKey(provider): string | null
• setApiKey(provider, key): void
• removeApiKey(provider): void
• clearAllApiKeys(): void
• getSelectedProvider(): AIProvider | null
• setSelectedProvider(provider): void
• getSelectedModel(provider): string | null
• setSelectedModel(provider, modelId): void
• hasAnyKeyConfigured(): boolean

Storage Keys

ogcops-ai-provider        → selected provider ID
ogcops-ai-model-{provider} → selected model per provider
ogcops-ai-key-{provider}   → API key per provider

Behavior

• Each provider stores its key independently — switching providers preserves other keys
• Model selection is per-provider — remembered when switching back
• hasAnyKeyConfigured() used to conditionally show AI features in the UI
• All functions are synchronous (localStorage is sync)

Security Considerations

• Keys stored in localStorage only — no cookies, no sessionStorage
• Keys never included in URL params (unlike other OGCOPS state)
• clearAllApiKeys() removes every ogcops-ai-* entry
• No encryption (localStorage is already accessible to same-origin JS — encryption would be security theater)

Acceptance Criteria

• All CRUD operations for keys, provider, and model selection work correctly
• Switching providers preserves previously saved keys
• clearAllApiKeys() removes all AI-related localStorage entries
• Functions handle missing/corrupted localStorage gracefully (return null, don't throw)
• Works in private/incognito mode (localStorage available but not persisted)

[anurag629]

Completed in dev branch.