Stop versioning DI and ISA95 packages as preview (#4686)

## Summary
Removes the **DI** (`Opc.Ua.Di*`) and **ISA95** (`Opc.Ua.ISA95*`)
package families from the preview-only set, so they ship with the stable
root version (e.g. `2.0.1` instead of `2.0.1-preview.N`).

- `version.targets`: drop the two `_IsPreviewPackage` conditions.
- `.azurepipelines/package-version-policy.ps1`: drop `ISA95|Di` from
`Test-PreviewPackageId`. It must match `version.targets`, because the
package-set validator fails if the two disagree.
- `PackageVersionPolicyTests`: ISA95/Di IDs are now expected to be
non-preview, they are removed from the classifier-agreement token list,
and the "already-preview base version" case now uses Robotics.
- Docs (`DeveloperGuide.md`, `ReleaseProcess.md`, `docs/README.md`): the
preview-family list no longer includes DI or ISA95, and the "preview
package" label is removed from the DI, Software Update (part of the DI
packages), and ISA-95 entries.

## Test
`dotnet test tests/Opc.Ua.Tools.Tests --filter PackageVersionPolicy`
(net10.0): 87/87 passed.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

docs/ReleaseProcess.md

@@ -37,7 +37,7 @@ without any other context.
   [Versioning](DeveloperGuide.md#versioning)). Every package in the solution
   shares the same root version except the **preview-only families**.
 - **Preview-only families** - the XRegistry, WoT Connectivity, Vision,
-  Robotics, Redundancy, Positioning, OpenUSD, ISA95, AI, and DI package
+  Robotics, Redundancy, Positioning, OpenUSD, and AI package
   families, the Robotics/Vision MCP extensions, and the OpenUSD connector
   tools. `version.targets` keeps these on a `-preview.N` suffix even when the
   root version is an exact stable release. The full, single source of truth
@@ -116,7 +116,7 @@ Every procedure below starts here.
        ConvertFrom-Json | ForEach-Object name
    ```
    Repeat for a representative sample of the preview-only families (at
-   minimum XRegistry, DI, and one MCP/connector package); they are versioned
+   minimum XRegistry, Robotics, and one MCP/connector package); they are versioned
    together but published independently, so check more than one. If any
    published number is greater than or equal to the committed
    `PreviewPackageBuildNumber`, raise it (in the same PR that changes the