agent: add separate glibc build with NVML support (#1618)

purego requires dynamic linking, so split the agent builds:
- Default: static binary without NVML (works on musl/alpine)
- Glibc: dynamic binary with NVML support via purego

Changes:
- Add glibc build tag to conditionally include NVML code
- Add beszel-agent-linux-amd64-glibc build/archive in goreleaser
- Update ghupdate to use glibc binary on glibc systems
- Switch nvidia dockerfile to golang:bookworm with -tags glibc

.goreleaser.yml

@@ -76,6 +76,18 @@ builds:
       - goos: windows
         goarch: riscv64
 
+  - id: beszel-agent-linux-amd64-glibc
+    binary: beszel-agent
+    main: internal/cmd/agent/agent.go
+    env:
+      - CGO_ENABLED=0
+    flags:
+      - -tags=glibc
+    goos:
+      - linux
+    goarch:
+      - amd64
+
 archives:
   - id: beszel-agent
     formats: [tar.gz]
@@ -89,6 +101,15 @@ archives:
       - goos: windows
         formats: [zip]
 
+  - id: beszel-agent-linux-amd64-glibc
+    formats: [tar.gz]
+    ids:
+      - beszel-agent-linux-amd64-glibc
+    name_template: >-
+      {{ .Binary }}_
+      {{- .Os }}_
+      {{- .Arch }}_glibc
+
   - id: beszel
     formats: [tar.gz]
     ids: