Generate dependency versions header from CMake (#22561)

## Summary

This PR introduces a CMake-generated header file containing all
dependency versions, eliminating the need for C++ code to depend on
Zig-exported version constants.

## Changes

- **New CMake script**: `cmake/tools/GenerateDependencyVersions.cmake`
that:
  - Reads versions from the existing `generated_versions_list.zig` file
- Extracts semantic versions from header files where available
(libdeflate, zlib)
- Generates `bun_dependency_versions.h` with all dependency versions as
compile-time constants
  
- **Updated BunProcess.cpp**:
  - Now includes the CMake-generated `bun_dependency_versions.h`
  - Uses `BUN_VERSION_*` constants instead of `Bun__versions_*` 
  - Removes dependency on Zig-exported version constants

- **Build system updates**:
  - Added `GenerateDependencyVersions` to main CMakeLists.txt
  - Added build directory to include paths in BuildBun.cmake

## Benefits

✅ Single source of truth for dependency versions
✅ Versions accessible from C++ without Zig exports
✅ Automatic regeneration during CMake configuration
✅ Semantic versions shown where available (e.g., zlib 1.2.8 instead of
commit hash)
✅ Debug output file for verification

## Test Results

Verified that `process.versions` correctly shows all dependency
versions:

```javascript
$ bun -e "console.log(JSON.stringify(process.versions, null, 2))"
{
  "node": "24.3.0",
  "bun": "1.2.22-debug",
  "boringssl": "29a2cd359458c9384694b75456026e4b57e3e567",
  "libarchive": "898dc8319355b7e985f68a9819f182aaed61b53a",
  "mimalloc": "4c283af60cdae205df5a872530c77e2a6a307d43",
  "webkit": "0ddf6f47af0a9782a354f61e06d7f83d097d9f84",
  "zlib": "1.2.8",
  "libdeflate": "1.24",
  // ... all versions present and correct
}
```

## Generated Files

- `build/debug/bun_dependency_versions.h` - Header file with version
constants
- `build/debug/bun_dependency_versions_debug.txt` - Human-readable
version list

🤖 Generated with [Claude Code](https://claude.ai/code)

---------

Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

scripts/write-versions.sh

@@ -1,35 +0,0 @@
-#!/bin/bash
-set -exo pipefail
-
-WEBKIT_VERSION=$(grep 'set(WEBKIT_TAG' "CMakeLists.txt" | awk '{print $2}' | cut -f 1 -d ')')
-MIMALLOC_VERSION=$(git rev-parse HEAD:./src/deps/mimalloc)
-LIBARCHIVE_VERSION=$(git rev-parse HEAD:./src/deps/libarchive)
-PICOHTTPPARSER_VERSION=$(git rev-parse HEAD:./src/deps/picohttpparser)
-BORINGSSL_VERSION=$(git rev-parse HEAD:./src/deps/boringssl)
-ZLIB_VERSION=$(git rev-parse HEAD:./src/deps/zlib)
-LOLHTML=$(git rev-parse HEAD:./src/deps/lol-html)
-TINYCC=$(git rev-parse HEAD:./src/deps/tinycc)
-C_ARES=$(git rev-parse HEAD:./src/deps/c-ares)
-ZSTD=$(git rev-parse HEAD:./src/deps/zstd)
-LSHPACK=$(git rev-parse HEAD:./src/deps/ls-hpack)
-LIBDEFLATE=$(git rev-parse HEAD:./src/deps/libdeflate)
-
-rm -rf src/generated_versions_list.zig
-echo "// AUTO-GENERATED FILE. Created via .scripts/write-versions.sh" >src/generated_versions_list.zig
-echo "" >>src/generated_versions_list.zig
-echo "pub const boringssl = \"$BORINGSSL_VERSION\";" >>src/generated_versions_list.zig
-echo "pub const libarchive = \"$LIBARCHIVE_VERSION\";" >>src/generated_versions_list.zig
-echo "pub const mimalloc = \"$MIMALLOC_VERSION\";" >>src/generated_versions_list.zig
-echo "pub const picohttpparser = \"$PICOHTTPPARSER_VERSION\";" >>src/generated_versions_list.zig
-echo "pub const webkit = \"$WEBKIT_VERSION\";" >>src/generated_versions_list.zig
-echo "pub const zig = @import(\"std\").fmt.comptimePrint(\"{}\", .{@import(\"builtin\").zig_version});" >>src/generated_versions_list.zig
-echo "pub const zlib = \"$ZLIB_VERSION\";" >>src/generated_versions_list.zig
-echo "pub const tinycc = \"$TINYCC\";" >>src/generated_versions_list.zig
-echo "pub const lolhtml = \"$LOLHTML\";" >>src/generated_versions_list.zig
-echo "pub const c_ares = \"$C_ARES\";" >>src/generated_versions_list.zig
-echo "pub const libdeflate = \"$LIBDEFLATE\";" >>src/generated_versions_list.zig
-echo "pub const zstd = \"$ZSTD\";" >>src/generated_versions_list.zig
-echo "pub const lshpack = \"$LSHPACK\";" >>src/generated_versions_list.zig
-echo "" >>src/generated_versions_list.zig
-
-zig fmt src/generated_versions_list.zig