feat(language): add complete PowerShell review support

Related to #470.

## Problem Statement

PowerShell `.ps1` files are already included in the review allowlist, but they currently fall back to the generic review rules. PowerShell module (`.psm1`) and data/manifest (`.psd1`) files are not allowlisted, even though they are standard PowerShell source formats analyzed by PSScriptAnalyzer.

Pester's conventional `*.Tests.ps1` files are also treated as production review inputs instead of test files.

## Proposed Solution

- Add `.psm1` and `.psd1` to the supported file types.
- Exclude conventional Pester `*.Tests.ps1` files.
- Add a PowerShell-specific review rule covering command injection, error and native-process semantics, pipeline output, credentials, remoting, module manifests, platform compatibility, and Pester test correctness.
- Map `.ps1`, `.psm1`, and `.psd1` files to the PowerShell rule.
- Add allowlist, exclusion, and rule-resolution tests.

A focused implementation is ready and will be linked in a pull request.

## Validation

- `make check`
- `make test`
- `make coverage` (91.5% total coverage)

Start at the review allowlist, file exclusion, and rule-resolution entry points; the issue does not name specific files. Run the listed make check and make test commands while adding coverage for .psm1, .psd1, *.Tests.ps1, and PowerShell rule resolution. Done means all three PowerShell formats resolve correctly, Pester files are excluded, and the stated validation commands pass.

Written by the indexing model from the issue text.