Multiple seconds building reachability constraints when using types from `pulumi_cloudflare`

### Summary

I'm experiencing a significant performance issue when type checking code that uses `pulumi_cloudflare`.

Using any type from the package causes ty to take ~12 minutes, while just importing it (without using any types) is instant. The much larger `pulumi_aws` package works fine.

### Reproduction

Tested on ty 0.0.12, Python 3.12.

**Slow case - using a type from pulumi_cloudflare:**

```python
# slow_cf.py
import pulumi_cloudflare

record = pulumi_cloudflare.Record(
"test",
zone_id="xxx",
name="test",
type="A",
content="1.2.3.4",
)
```

```
$ ty check slow_cf.py
All checks passed!
Took 12m29.81s
```

**Fast case - import only, no usage:**

```python
# fast_cf.py
import pulumi_cloudflare
```

```
$ ty check fast_cf.py
All checks passed!
Took 0.058s
```

**pulumi_aws works fine:**

```python
# aws_test.py
import pulumi_aws

bucket = pulumi_aws.s3.Bucket("test")
```

```
$ ty check aws_test.py
All checks passed!
Took 0.241s
```

### Environment

- ty: 0.0.12
- Python: 3.12
- pulumi_cloudflare: 6.12.0
- pulumi_aws: 7.16.0
- macOS Tahoe (M3 Max, 36GB)

### Observations

I looked into why this might be happening (though I could be wrong about the details):

- `pulumi_cloudflare` is smaller (42MB) than `pulumi_aws` (121MB), yet much slower
- `pulumi_cloudflare` appears to have a more monolithic structure - I noticed `_inputs.py` is quite large (~88K lines) compared to `pulumi_aws` which seems to split things across many files
- Both packages use `Input[T] = Union[T, Awaitable[T], Output[T]]` pattern with TypedDicts

I found that mypy has a similar issue documented in python/mypy#17231, where Pulumi's TypedDict + Union patterns cause performance problems. Pyright apparently handles this better. Not sure if the same root cause applies here.

This might be related to #240 (large union benchmarks), though I'm not certain.

### Workaround

Excluding the folder from ty checking works for now:

```toml
[tool.ty.src]
exclude = ["path/to/code/using/cloudflare/"]
```

### Questions

- Is this a known pattern that causes issues for ty?
- Any other workarounds besides excluding?
- Any plans for handling this?

Thanks for the amazing tool!

### Version

ty 0.0.12 (4b74e4ded 2026-01-14)

Start by running `ty check slow_cf.py` and compare it with `fast_cf.py` and `aws_test.py` using the versions in the report. Investigate why using `pulumi_cloudflare.Record` triggers prolonged reachability-constraint building, with #240 and the linked mypy report as context; done means the reproduced check completes without the multi-minute slowdown and has regression coverage.

Written by the indexing model from the issue text.