Record the Windows beta8 preview candidate

[coneilen]

Summary

Record the immutable, unpublished Windows beta8 preview candidate and its
LFS-aware Dev Box handoff.

Beta7 is failed/superseded. On the attended Dev Box, native Ctrl+O registered
Core in the production daemon, but the shell never showed the project. #633
fixes the cause: the shell discarded the daemon's canonical-path reply to its
own folder open, and did not correlate the daemon's uppercase request IDs. All
runtime qualification gates remain open.

Changes

• Record source/tag/package/payload/executable/provider/toolchain identities for
  0.1.78-windows.beta8 at 1bd0398108dd8e72e51bcf84a2af534d1531ab32.
• Record the Accept the daemon's canonical reply for the shell's own folder open #633 root cause and its evidence, and note that the beta7
  fresh-relaunch snapshot is inconclusive.
• Record source-custody verification and file-only offline restore with 43/43
  LFS files materialized, and the 8/8 versioned handoff inventory.
• Move beta7 to history as failed/superseded and immutable. Keep beta1 through
  beta6 unchanged.
• Keep Exact artifact complete, the other six gates open, and parity at
  98/62/36.

Test plan

RED: zig test src\App.zig --test-filter "graph publication" before #633 -> 8 passed, 2 failed; daemon canonical-path reply dropped and uppercase rejection uncorrelated
GREEN: Tools\windows\Tests\ScrubbedShellStartup.Live.Tests.ps1 against the extracted beta8 package binaries -> PASS; executed=5
REGRESSION: Tools\windows\release.ps1 -Tag 0.1.78-windows.beta8 -> repository verify 1 PASS; extracted setup verify 1 PASS; payload 50; binary reports deferred

• Source custody Create and Verify passed with 43 objects for 43 files.
• File-only offline restore through the included Restore-GraphCodeSource.ps1
  gave exact detached HEAD/tag, zero remotes, clean status, and 43/43
  materialized LFS files.
• Handoff inventory: 8/8 hashes verified; hashes.sha256 SHA-256
  9b06f2efea1d026e22a541cec4ee5c7154f3127101b693f2f4ae68ab6857c19f.
• No tag or release was pushed or published.
• No native picker, Dev Box, backend, destructive fixture, Worktrees, Nod, dump,
  or publication evidence is claimed.
• macOS make test and make check were not run because this is a
  documentation-only Windows candidate evidence update.

Checklist

• I have read the Contributing Guidelines
• I have signed off my commits (git commit -s) per the DCO
• Tests pass locally (make test)
• Code follows the existing style (make check)
• I added the test/contract before the implementation and observed the intended RED failure