Skyrim Forge 5.1.4 — UTF-8 config reads, space-tolerant Hermes test, reproducible natives

Encoding correctness, a test that only passed on space-free paths, and a
release profile that no longer reproduced.

• Provider configs are read as UTF-8, not the ANSI codepage. On Windows
  PowerShell 5.1, Get-Content -Raw without an explicit -Encoding decodes
  using the ANSI codepage (Windows-1252), not UTF-8. Register-MCP.ps1 read the
  user's Kimi mcp.json that way and wrote the parsed object straight back, so
  every non-ASCII character in that file would have been replaced by mojibake.
  Measured on an mcp.json carrying one em dash: Get-Content -Raw turned 1 em
  dash into 0 and produced 1 mojibake sequence; ReadAllText preserved it.
  Four call sites moved to [IO.File]::ReadAllText across Register-MCP.ps1,
  Install-Forge-Skill.ps1 and workers/SkyrimForge.UIWorker.ps1. The UI
  worker's path is caller-supplied and may be relative, so it is resolved with
  Convert-Path first: .NET resolves relative paths against the process working
  directory, not PowerShell's current location.

• The Hermes registration test asserted an unquoted command line. PowerShell
  quotes any argument containing a space, so an install under a path such as
  S:\Apps\Skyrim Tools\... logs --command "S:\Apps\...". That quoting is
  required -- without it hermes would receive --command S:\Apps\Skyrim and
  Tools\... as two separate arguments -- but the test compared against the bare
  form and therefore only passed when the install path contained no spaces. The
  registration code was correct; the assertion now strips quotes before
  comparing.

• The shipped native helpers no longer reproduced from source. Running
  scripts/validate_repository.py against a clean checkout of 5.1.3 reported
  both binaries as "not reproducible under the -buildvcs=false release profile":
  they had been built with a different Go toolchain than the one the profile
  now produces. Rebuilt deterministically, so a from-source rebuild matches the
  published bytes again. CHECKSUMS-SHA256.txt, MANIFEST.json, SBOM.spdx.json
  and BUILD-RECEIPT.json are regenerated to match.

Validation: scripts/validate_repository.py -> PASS, no errors (5.1.3
reported FAIL on the reproducibility check). python -m unittest discover -s tests -> 151 tests, OK. PowerShell parser gate -> PASS (9 scripts).