RustCrypto / Dalek Dependency Line Conflicts with russh 0.61

When using IronRDP and `russh 0.61.2` in the same Cargo workspace, dependency resolution fails because the two stacks currently depend on different RustCrypto / Dalek prerelease lines.

`russh 0.61.2` uses the newer line:

- `curve25519-dalek = 5.0.0-rc.0`
- `ed25519-dalek = 3.0.0-rc.0`
- `x25519-dalek = 3.0.0-rc.0`
- `p256 / p384 / p521 = 0.14.0-rc.10`

The IronRDP authentication path currently reaches older exact pins through `sspi-rs` and `picky-rs`, for example:

- `curve25519-dalek = 5.0.0-pre.6`
- `ed25519-dalek = 3.0.0-pre.6`
- `x25519-dalek = 3.0.0-pre.6`
- `p256 / p384 / p521 = 0.14.0-rc.9`

Because these are exact prerelease pins, Cargo cannot resolve both lines together.

The first resolver error is:

```text
failed to select a version for `curve25519-dalek`

previously selected package `curve25519-dalek v5.0.0-rc.0`
... which satisfies dependency `curve25519-dalek = "=5.0.0-rc.0"` of package `russh v0.61.2`

versions that meet the requirements `=5.0.0-pre.6` are: 5.0.0-pre.6
... required by package `picky v7.0.0-rc.23`
... required by package `ironrdp-connector`
```

I tested a downstream fix by moving the IronRDP authentication dependency chain to the same dependency line as `russh 0.61.2`.

Commits:

- picky-rs: https://github.com/fluxterm/picky-rs/commit/01b584fbd60ccd0f579f4f20b5f4d49ca3e457e3
- sspi-rs: https://github.com/fluxterm/sspi-rs/commit/7aae095957cd56075d68be56cfeca15610d16dce
- IronRDP: https://github.com/fluxterm/IronRDP/commit/1c3ce7aaf8f90f999d6f2e15be1d7869261c9f5e

## What Changed

In `picky-rs`, the main change is aligning the crypto pins with the `russh 0.61.2` line:

- `curve25519-dalek`: `5.0.0-pre.6` -> `5.0.0-rc.0`
- `ed25519-dalek`: `3.0.0-pre.6` -> `3.0.0-rc.0`
- `x25519-dalek`: `3.0.0-pre.6` -> `3.0.0-rc.0`
- `p256 / p384 / p521`: `0.14.0-rc.9` -> `0.14.0-rc.10`
- `ecdsa`: `0.17.0-rc.17` -> `0.17.0-rc.18`
- `elliptic-curve`: `0.14.0-rc.32` -> `0.14.0-rc.33`
- `ff / group`: `0.14.0-pre.0` -> `0.14.0`

In `sspi-rs`, the same dependency line needs to be used consistently, including DPAPI-related pins:

- `rsa`: `0.10.0-rc.17` -> `0.10.0-rc.18`
- `pkcs8`: `0.11.0-rc.11` -> `0.11.0`
- `signature`: `3.0.0-rc.10` -> `3.0.0`
- `pbkdf2`: `0.13.0-rc.10` -> `0.13.0`

`picky`, `picky-asn1`, `picky-asn1-der`, `picky-asn1-x509`, and `picky-krb` also need to resolve from the same source/version line. Otherwise Cargo can compile duplicate ASN.1 crate instances and produce type mismatch errors.

In IronRDP, the connector side needs to use the updated `sspi-rs` / `picky-rs` line. I also changed the direct `picky` dependency in `ironrdp-connector` to avoid default features:

```toml
picky = { version = "=7.0.0-rc.23", default-features = false, features = ["x509"] }
```

This is enough for the connector usage and avoids pulling unrelated crypto dependencies.

The old `uuid <1.21` constraint in `ironrdp-mstsgu` can also be removed once the older `picky` / `rand_core` line is gone.

## Result

With these three changes applied together, IronRDP can coexist with `russh 0.61.2` in the same dependency graph, and `curve25519-dalek` resolves to a single version:

```text
curve25519-dalek v5.0.0-rc.0
```

I wanted to share this dependency-line mismatch and the downstream fix that made the combined dependency graph resolve.