fix(CLI-02): make Rust crate buildable outside the repository

build.rs resolved the .proto files via a monorepo-relative path and packaging
relied on `cargo publish --no-verify` to hide the resulting failure. Vendor the
three canonical protos into clients/rust/protos/, resolve them via
CARGO_MANIFEST_DIR (in-repo path preferred, vendored fallback for the packaged
crate), ship them via Cargo.toml `include`, and drop `--no-verify` from
pack-clients.ps1.

archreview: CLI-02 (P1). Verified: cargo fmt/check/test (28) + clippy -D warnings,
and `cargo package` (no --no-verify) compiles standalone in the isolated staging
dir — the out-of-repo proof. Vendored-proto drift is guarded by check-codegen.ps1.

scripts/pack-clients.ps1

@@ -187,7 +187,9 @@ function Invoke-PackRust {
         }
 
         Write-Host 'Running cargo package...'
-        & cargo package --no-verify
+        # No --no-verify: the crate vendors its protos (clients/rust/protos) so
+        # the verify build proves it compiles standalone from the tarball (CLI-02).
+        & cargo package
         if ($LASTEXITCODE -ne 0) { throw 'cargo package failed.' }
 
         $packageDir = Join-Path $rustDir 'target/package'
@@ -207,7 +209,7 @@ function Invoke-PackRust {
         Write-Host 'Publishing Rust crate to Gitea...' -ForegroundColor Yellow
         Push-Location (Join-Path $RepoRoot 'clients/rust')
         try {
-            & cargo publish --no-verify --registry dohertj2-gitea
+            & cargo publish --registry dohertj2-gitea
             if ($LASTEXITCODE -ne 0) { throw 'cargo publish failed.' }
         } finally { Pop-Location }
     }