Various bug fixes (#778)

zencore fixes:
- filesystem.cpp: ReadFile error reporting logic
- compactbinaryvalue.h: CbValue::As*String error reporting logic

zenhttp fixes:
- httpasio BindAcceptor would `return 0;` in a function returning `std::string` (UB)
- httpsys async workpool initialization race

zenstore fixes:
- cas.cpp: GetFileCasResults Results param passed by value instead of reference (large chunk results were silently lost)
- structuredcachestore.cpp: MissCount unconditionally incremented (counted hits as misses)
- cacherpc.cpp: Wrong boolean in Incomplete response array (all entries marked incomplete)
- cachedisklayer.cpp: sizeof(sizeof(...)) in two validation checks computed sizeof(size_t) instead of struct size
- buildstore.cpp: Wrong hash tracked in GC key list (BlobHash pushed twice instead of MetadataHash)
- buildstore.cpp: Removed duplicate m_LastAccessTimeUpdateCount increment in PutBlob

zenserver fixes:
- httpbuildstore.cpp: Reversed subtraction in HTTP range calculation (unsigned underflow)
- hubservice.cpp: Deadlock in Provision() calling Wake() while holding m_Lock (extracted WakeLocked helper)
- zipfs.cpp: Data race in GetFile() lazy initialization (added RwLock with shared/exclusive paths)

1 files changed, 6 insertions, 3 deletions

diff --git a/src/zenserver/frontend/frontend.cpp b/src/zenserver/frontend/frontend.cpp
index 2b157581f..1cf451e91 100644
--- a/src/zenserver/frontend/frontend.cpp
+++ b/src/zenserver/frontend/frontend.cpp
@@ -38,7 +38,7 @@ HttpFrontendService::HttpFrontendService(std::filesystem::path Directory, HttpSt
 #if ZEN_EMBED_HTML_ZIP
 	// Load an embedded Zip archive
 	IoBuffer HtmlZipDataBuffer(IoBuffer::Wrap, gHtmlZipData, sizeof(gHtmlZipData) - 1);
-	m_ZipFs = ZipFs(std::move(HtmlZipDataBuffer));
+	m_ZipFs = std::make_unique<ZipFs>(std::move(HtmlZipDataBuffer));
 #endif
 
 	if (m_Directory.empty() && !m_ZipFs)
@@ -157,9 +157,12 @@ HttpFrontendService::HandleRequest(zen::HttpServerRequest& Request)
 		}
 	}
 
-	if (IoBuffer FileBuffer = m_ZipFs.GetFile(Uri))
+	if (m_ZipFs)
 	{
-		return Request.WriteResponse(HttpResponseCode::OK, ContentType, FileBuffer);
+		if (IoBuffer FileBuffer = m_ZipFs->GetFile(Uri))
+		{
+			return Request.WriteResponse(HttpResponseCode::OK, ContentType, FileBuffer);
+		}
 	}
 
 	Request.WriteResponse(HttpResponseCode::NotFound, HttpContentType::kText, "Not found"sv);