Add vendor fetch

pkgs/nvft/README.md

@@ -0,0 +1,55 @@
+# nvft (nvfetcher + tools)
+
+A Nix package that combines nvfetcher source updates with automatic Go vendor hash calculation.
+
+## Usage
+
+```bash
+# Enter the nix-shell (makes nvft available)
+nix-shell
+
+# Run the updater
+nvft
+```
+
+This will:
+1. Save existing vendorHash and source hashes
+2. Run `nvfetcher` to update all source versions and hashes in `_sources/generated.nix`
+3. Restore saved vendorHash values
+4. Check if source hash changed - if yes, recalculate vendorHash; if no, skip (fast!)
+5. Update `vendorHash` in `_sources/generated.nix` only if needed
+
+## Configuration
+
+Go packages that need vendor hash updates are configured in the `GO_PACKAGES` array within the script.
+
+Currently configured packages:
+- `mender-cli` -> `modules/home/terminal/hr/mender-cli.nix`
+
+To add more Go packages, edit `pkgs/nvft/default.nix` and add entries to the `GO_PACKAGES` array.
+
+## How it Works
+
+For each Go package:
+1. Compares old vs new source hash to detect updates
+2. If source unchanged, keeps existing vendorHash (fast)
+3. If source changed, creates a temporary build with `lib.fakeHash`
+4. Attempts to build, which fails with the correct hash
+5. Extracts the correct hash from the error message
+6. Updates `vendorHash` directly in `_sources/generated.nix` alongside the source information
+
+## Package Usage
+
+Go packages read vendorHash from the sources:
+
+```nix
+let
+  src = sources.mender-cli;
+in
+buildGoModule {
+  inherit (src) pname version src vendorHash;
+  # ... rest of package
+}
+```
+
+The vendorHash is stored in `_sources/generated.nix` alongside the version and source hash, keeping all auto-generated values in one place.