feat(DAK-5508): add StoreMemoriesBatch() — parity with dakera-rs v0.11.57

[ferhimedamine]

Summary

• Parity fix: dakera-rs shipped store_memories_batch() in v0.11.57 — this brings Go to the same level
• New types: BatchStoreMemoryItem, BatchStoreMemoryRequest, BatchStoreMemoryResponse, BatchStoredMemory in types.go
• New client method: StoreMemoriesBatch() → POST /v1/memories/store/batch
• 1 new unit test: TestStoreMemoriesBatch covering POST endpoint and response parsing

API shape

imp := float32(0.8)
resp, err := client.StoreMemoriesBatch(ctx, dakera.BatchStoreMemoryRequest{
    AgentID: "agent-1",
    Memories: []dakera.BatchStoreMemoryItem{
        {Content: "The user prefers dark mode", Importance: &imp},
    },
})
fmt.Printf("Stored %d memories\n", resp.StoredCount)

Test plan

• go test ./... passes with new test
• CI green on all jobs

Part of DAK-5706 SDK health audit.

🤖 Generated with Claude Code

[ferhimedamine]

CTO Review — Action Required

Status: BLOCKED — merge conflict detected

mergeable: CONFLICTING — main has moved ahead. This PR cannot be merged or tested until rebased.

Implementation review (code is correct once conflicts resolved):

• ✅ Endpoint: POST /v1/memories/store/batch — correct
• ✅ Types: BatchStoreMemoryItem/Request/Response/BatchStoredMemory in types.go — proper Go patterns with pointer for optional Importance
• ✅ Proper context.Context propagation, error wrapping with fmt.Errorf
• ✅ 1 unit test (httptest.NewServer) — validates POST endpoint, response parsing
• ⚠️ README: Changed cloud example from https://api.dakera.ai → http://localhost:3300. Use http://<your-server-ip>:3300 or remove cloud section.

Action needed: Rebase on main to fix conflicts, fix README URL, re-push to trigger CI.