Fix Windows CI cargo test crash (STATUS_ENTRYPOINT_NOT_FOUND) and optimize local date bucketing

[BrianWong05]

Fix Windows CI cargo test crash and optimize local date bucketing

Problem

The windows-latest leg of CI failed on every run:

Running unittests src\lib.rs (...\tokenledger_lib-*.exe)
error: test failed, to rerun pass `--lib`
Caused by:
  process didn't exit successfully: ... (exit code: 0xc0000139, STATUS_ENTRYPOINT_NOT_FOUND)

The test executable died before running a single test.

Root cause

Known Tauri issue (tauri-apps/tauri#13419, #14580, originating in PR #4383):

• tauri-plugin-dialog links entry points that only exist in Common-Controls v6, which Windows activates solely from the executable's application manifest.
• tauri-build embeds that manifest into binaries only (rustc-link-arg-bins), never into test executables — so the test exe loads ComCtl32 v5 and fails import resolution at process start.
• Tauri's own __TAURI_WORKSPACE__ workaround resolves the manifest relative to its own monorepo and cannot work downstream (the previous attempt in .cargo/config.toml had no effect).

Fix

• Vendor tauri-build's windows-app-manifest.xml into src-tauri/ (byte-for-byte copy of the 2.6.3 default).
• In build.rs (Windows MSVC only): suppress tauri-build's per-bin manifest via new_without_app_manifest(), then embed the vendored manifest into every link target — binaries and test executables alike — via cargo:rustc-link-arg=/MANIFEST:EMBED + /MANIFESTINPUT:. This mirrors what upstream does in its own workspace.
• Remove the ineffective __TAURI_WORKSPACE__ env hack from .cargo/config.toml.
• Non-MSVC targets (macOS, Linux, Windows-gnu) are untouched.

Also in this branch

• Local date bucketing: replaces per-row strftime(..., 'localtime') with a cached tokenledger_local_bucket SQLite scalar function (chrono resolves offsets in memory instead of crossing into the OS per row), plus a release-mode performance standard (npm run perf, 100k-event budgets) and an equivalence test against SQLite's strftime reference. tokenledger_local_bucket never yields NULL — ambiguous readings take the earlier offset, unmappable instants fall back to UTC.
• Test-only app_context mocking to avoid GUI resource loading under the mock runtime.
• crate-type narrowed to ["lib"] (desktop-only app; no mobile targets).

Verification

• CI green on all three platforms (macos-latest, windows-latest, ubuntu-22.04) — the Windows cargo test leg that this branch targets now runs the full suite.
• Local suite: 372 + 6 tests passing.