Record the Windows beta16 preview candidate

[coneilen]

Summary

Record the immutable, unpublished Windows beta16 preview candidate and its
LFS-aware Dev Box handoff.

Beta15 is failed and superseded. Reopening loop A after loop B left B's session
in a stray selected tab, because every graph refresh bound loops to terminal
slots in graph order. #656 fixes this.

Approval A stays AvailableInspectionOnly for Worktrees. All runtime
qualification gates remain open.

Changes

• Record source/tag/package/payload/executable/provider/toolchain identities for
  0.1.78-windows.beta16 at d75bb952f725fb3f15d6c9b812c973b2ea5b49b0.
• Record the Bind only the open loop when the Windows graph refreshes #656 root cause and fix, and the passing full local validation.
• Record custody, the offline restore (43/43 LFS) and the 8/8 handoff.
• Move beta15 to history. Beta1–beta15 are unchanged.
• Keep parity at 98/60/38.

Test plan

RED: PR 656 zig test src\App.zig --test-filter "attended activation reopening" with the pre-fix refreshWorkspace -> 0 passed, 2 failed; graph refresh bound loop-b into slot 1
GREEN: Tools\windows\validate.ps1 -Task windows-shell -SkipTrayLive -ShellValidationRoot C:\v7 at d75bb95 -> VALIDATE_EXIT=0; 55/55 sections; App 873/873; scrubbed 5/5; real daemon round trip PASS; live UIA gate PASS
REGRESSION: Tools\windows\release.ps1 -Tag 0.1.78-windows.beta16 -> repository verify 1 PASS; extracted setup verify 1 PASS; payload 50; binary reports available; packaged scrubbed startup 5/5

• The RED line is from Bind only the open loop when the Windows graph refreshes #656's own evidence. I did not reproduce it locally.
• Source custody Create and Verify passed with 43 objects for 43 files.
• The file-only offline restore gave an exact detached HEAD/tag, zero remotes,
  a clean status, and 43/43 materialized LFS files.
• Handoff inventory: 8/8 verified; hashes.sha256 SHA-256
  78ea03fada20125138911a2221e34b5d719ebee3d1d6cac8139a62470f0777a6.
• Not claimed: Dev Box A → B → A, Worktrees reclaim, backend, destructive, Nod,
  dump or publication evidence.
• No tag or release was pushed or published.
• macOS make test and make check were not run; this is a
  documentation-only change.

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