Add Debian packaging support for socktop-agent (#25)

* Add Debian packaging support with cargo-deb

- Add cargo-deb metadata to socktop and socktop_agent Cargo.toml
- Create systemd service file for socktop_agent
- Add postinst/postrm maintainer scripts for user/group management
- Create GitHub Actions workflow to build .deb packages for AMD64 and ARM64
- Add comprehensive documentation in docs/DEBIAN_PACKAGING.md
- Packages will be available as artifacts on every push
- Automatic GitHub releases for version tags

* Add summary documentation for debian packaging

* fix unit test, move to macro cargo_bin!

* hotfix for issue with socktop agent not creating ssl certificate on first launch after upgrade of axum server version.

* Add helpful post-install message to guide users on enabling socktop-agent service

* Fix CI build by installing libdrm development dependencies

* Fix package rename script - cargo-deb already includes architecture in filename

* Make GPU support optional to enable RISC-V builds without libdrm

- Add 'gpu' feature flag (enabled by default)
- Make gfxinfo dependency optional
- Provide no-op GPU metrics when gpu feature disabled
- Disable GPU support for RISC-V builds in CI (libdrm unavailable)
- All other architectures (amd64, arm64, armhf) still get GPU support

* feature gate GPU stats for arm v7

* specify correct package names.

* install aarch64-linux-gnu-gcc build dep

* specify correct package name

* add RISC-V GCC compiler

* add .cargo to gitignore to elimicate issue with riscv64-linux-gnu-gcc linker in config.toml

* add gcc-arm-linux-gnueabihf linker fore armv7

* set correct x-compile lib gcc-aarch64-linux-gnu for arm64 builds.

* add ports.ubuntu.com to sources

* Add ARM64 as a foreign architecture

* fixe for ARM64 build.

* security.ubuntu.com` aNNOYING

* apt repo github page

* copy output to apt repo

* fix secrets path

* fix secrets path

* change build dep

* Fix postinst message box alignment

* ci(deb): restrict APT publish to v* release tags

Previously the workflow built and published on every push to master
and feature/debian-packaging in addition to v* tags. That meant the
gh-pages APT repo got overwritten on every commit with same-version
.debs, causing apt clients to see a phantom "update available" each
time and burning ~5-10 min of cross-compile CI per merge.

After this change:
  - PRs into master still cross-build .debs as a sanity check.
  - v* tags build, publish to gh-pages, and create a GitHub release.
  - workflow_dispatch remains as the manual escape hatch.
  - master pushes no longer trigger this workflow (ci.yml still runs).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docs/cross-compiling.md

@@ -2,6 +2,8 @@
 
 This guide explains how to cross-compile the socktop_agent on various host systems and deploy it to a Raspberry Pi. Cross-compiling is particularly useful for older or resource-constrained Pi models where native compilation might be slow.
 
+**Note:** GPU monitoring support is not available on ARMv7 (32-bit) and RISC-V architectures due to library limitations. When building for these platforms, the `--no-default-features` flag must be used to disable GPU support.
+
 ## Cross-Compilation Host Setup
 
 Choose your host operating system:
@@ -23,8 +25,9 @@ sudo apt update
 sudo apt install gcc-aarch64-linux-gnu libc6-dev-arm64-cross libdrm-dev:arm64
 
 # For 32-bit Raspberry Pi (armv7)
+# Note: GPU support not available on armv7
 sudo apt update
-sudo apt install gcc-arm-linux-gnueabihf libc6-dev-armhf-cross libdrm-dev:armhf
+sudo apt install gcc-arm-linux-gnueabihf libc6-dev-armhf-cross
 ```
 
 ### Setup Rust Cross-Compilation Targets
@@ -65,9 +68,8 @@ sudo pacman -S aarch64-linux-gnu-gcc
 yay -S aarch64-linux-gnu-libdrm
 
 # For 32-bit Raspberry Pi (armv7)
+# Note: GPU support not available on armv7
 sudo pacman -S arm-linux-gnueabihf-gcc
-# Install libdrm for armv7 using an AUR helper
-yay -S arm-linux-gnueabihf-libdrm
 ```
 
 ### Setup Rust Cross-Compilation Targets
@@ -114,8 +116,8 @@ cd path/to/socktop
 # For 64-bit Raspberry Pi
 docker run --rm -it -v "$(pwd)":/home/rust/src messense/rust-musl-cross:aarch64-musl cargo build --release --target aarch64-unknown-linux-musl -p socktop_agent
 
-# For 32-bit Raspberry Pi
-docker run --rm -it -v "$(pwd)":/home/rust/src messense/rust-musl-cross:armv7-musleabihf cargo build --release --target armv7-unknown-linux-musleabihf -p socktop_agent
+# For 32-bit Raspberry Pi (without GPU support)
+docker run --rm -it -v "$(pwd)":/home/rust/src messense/rust-musl-cross:armv7-musleabihf cargo build --release --target armv7-unknown-linux-musleabihf -p socktop_agent --no-default-features
 ```
 
 The compiled binaries will be available in your local target directory.
@@ -133,11 +135,11 @@ The recommended approach for Windows is to use Windows Subsystem for Linux (WSL2
 After setting up your environment, build the socktop_agent for your target Raspberry Pi:
 
 ```bash
-# For 64-bit Raspberry Pi
+# For 64-bit Raspberry Pi (with GPU support)
 cargo build --release --target aarch64-unknown-linux-gnu -p socktop_agent
 
-# For 32-bit Raspberry Pi
-cargo build --release --target armv7-unknown-linux-gnueabihf -p socktop_agent
+# For 32-bit Raspberry Pi (without GPU support)
+cargo build --release --target armv7-unknown-linux-gnueabihf -p socktop_agent --no-default-features
 ```
 
 ## Transfer the Binary to Your Raspberry Pi
@@ -161,11 +163,12 @@ SSH into your Raspberry Pi and install the required dependencies:
 ```bash
 ssh pi@raspberry-pi-ip
 
-# For Raspberry Pi OS (Debian-based)
+# For Raspberry Pi OS (Debian-based) - 64-bit only
+# (32-bit armv7 builds don't require these)
 sudo apt update
 sudo apt install libdrm-dev libdrm-amdgpu1
 
-# For Arch Linux ARM
+# For Arch Linux ARM - 64-bit only
 sudo pacman -Syu
 sudo pacman -S libdrm
 ```