[BUG] LanceDBStorage.list_records() returns oldest records instead of newest first due to premature query truncation

Description

In LanceDBStorage (lib/crewai/src/crewai/memory/storage/lancedb_storage.py), list_records() is documented to return records ordered by created_at descending:

"List records in a scope, newest first. Returns: List of MemoryRecord, ordered by created_at descending."

However, list_records() currently returns the oldest records in the table rather than the newest.

Root Cause:
In lancedb_storage.py lines 507–510:

rows = self._scan_rows(scope_prefix, limit=limit + offset)
records = [self._row_to_record(r) for r in rows]
records.sort(key=lambda r: r.created_at, reverse=True)
return records[offset : offset + limit]

### Steps to Reproduce

```text
1. Initialize LanceDBStorage in a temporary directory.
2. Insert 10 records with sequential created_at timestamps (rec_0 oldest, rec_9 newest).
3. Call storage.list_records(limit=3).
4. Inspect the returned IDs.

### Expected behavior

list_records(limit=3) should return the 3 most recently created records:
['rec_9', 'rec_8', 'rec_7']

### Screenshots/Code snippets

import tempfile
from datetime import datetime, timezone, timedelta
from crewai.memory.storage.lancedb_storage import LanceDBStorage
from crewai.memory.types import MemoryRecord

with tempfile.TemporaryDirectory() as tmpdir:
    storage = LanceDBStorage(path=tmpdir)
    base_time = datetime.now(timezone.utc)
    
    # Insert 10 records: rec_0 is oldest, rec_9 is newest
    records = [
        MemoryRecord(
            id=f"rec_{i}",
            content=f"content {i}",
            created_at=base_time + timedelta(minutes=i),
            embedding=[0.1] * 1536
        )
        for i in range(10)
    ]
    storage.save(records)

    # Request the 3 newest records
    results = storage.list_records(limit=3)
    print("Returned IDs:", [r.id for r in results])
    # Expected: ['rec_9', 'rec_8', 'rec_7']
    # Actual:   ['rec_2', 'rec_1', 'rec_0']

### Operating System

macOS Sonoma

### Python Version

3.12

### crewAI Version

1.15.21

### crewAI Tools Version

1.15.21

### Virtual Environment

Venv

### Evidence

Running the reproduction script outputs:

Returned IDs: ['rec_2', 'rec_1', 'rec_0']

The 3 oldest records (rec_0, rec_1, rec_2) were fetched and sorted descending, while the actual newest records (rec_9, rec_8, rec_7) were truncated at the storage layer and never returned.

### Possible Solution

In `LanceDBStorage.list_records`:
Do not truncate `_scan_rows` before sorting. Scan the candidate rows in the scope (using the default `_SCAN_ROWS_LIMIT` of 50,000, identical to how `get_scope_info` works and how `QdrantEdgeStorage.list_records` works), sort by `created_at` descending, and then apply the pagination slice:

```python
def list_records(
    self, scope_prefix: str | None = None, limit: int = 200, offset: int = 0
) -> list[MemoryRecord]:
    rows = self._scan_rows(scope_prefix)
    records = [self._row_to_record(r) for r in rows]
    records.sort(key=lambda r: r.created_at, reverse=True)
    return records[offset : offset + limit]

### Additional context

```text
I have verified this reproduction locally and have the fix and regression unit test ready to submit as a PR if approved.