bug(report): PackageListEntry JSON field names inconsistent with PackageEntry

[rocketman-code]

Current Behavior

`PackageEntry` (used in trace reports) uses `total_size_bytes` and `file_count`, while `PackageListEntry` (used in packages reports) uses `size` and `files` for the same semantic data. This inconsistency makes the JSON API harder to consume.

Expected Behavior

Both types should use consistent field names for the same concepts. `PackageListEntry` should use `total_size_bytes` and `file_count` to match `PackageEntry`.

Context

Users consuming the JSON output programmatically need to handle different field names for the same data depending on which command they ran.

Technical Details

Relevant Code

`src/report.rs:280-286` -- PackageEntry:
```rust
pub struct PackageEntry {
pub name: String,
pub total_size_bytes: u64,
pub file_count: u32,
pub chain: Vec,
}
```

`src/report.rs:356-361` -- PackageListEntry:
```rust
pub struct PackageListEntry {
pub name: String,
pub size: u64,
pub files: u32,
}
```