docs: add verified build instructions; fix bincmp ssdeep API

- README "Building From Source" section covering all Go and Rust tools;
  every command tested (rustc, go build, goipgrep make build/test)
- bincmp: ssdeep.HashFromFile does not exist in pinned ssdeep v0.4.0,
  switch to FuzzyFilename; fix two go vet warnings
- ignore in-place build outputs for bincmp/gopname/goinfo

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

README.md

@@ -302,6 +302,48 @@ All Go code lives under `projects/go-tools/` (one directory per tool).
 - `projects/puzzlebox/`: puzzle-solving and voxel-based search experiments with several solver variants.
 - `projects/timesketch/deploy_timesketch.sh`: deployment helper for Timesketch.
 
+## Building From Source
+
+No compiled binaries are checked in — everything is built from source on demand.
+All commands below were verified to work; the Python tools in `tools/` need no build step.
+
+Go tools with a `go.mod` (build from inside the tool directory so the module is picked up):
+
+```sh
+cd projects/go-tools/bincmp  && go build -o bincmp .     # fuzzy binary/dir comparison
+cd projects/go-tools/gopname && go build -o gopname .    # process-title demo
+cd projects/go-tools/goinfo  && go build -o goinfo .     # file/system info
+cd archive/experimental/go/tarsum && go build -o tarsum .
+```
+
+Single-file Go tools (stdlib only, build from anywhere):
+
+```sh
+go build -o csv2json projects/go-tools/csv2json/csv2json.go
+go build -o gosoft   projects/go-tools/gosoft/gosoft.go
+go build -o gouniq   archive/experimental/go/gouniq/gouniq.go
+go build -o gobetween archive/experimental/go/gobetween/gobetween.go
+```
+
+goipgrep (the full project) has its own build tooling:
+
+```sh
+cd projects/go-tools/goipgrep
+make build        # or: ./scripts/build.sh — output lands in dist/ipgrep
+make test
+```
+
+Rust tools (single files, no cargo project needed):
+
+```sh
+rustc -O archive/experimental/rust/uniq.rs    -o uniq
+rustc -O archive/experimental/rust/uniq2.rs   -o uniq2
+rustc -O archive/experimental/rust/between.rs -o between
+```
+
+Build outputs (`dist/`, `bin/`, `*.exe`, `*.test`, and the per-tool binary names
+above) are gitignored — do not commit compiled artifacts.
+
 ## `config/`: Shell, Desktop, and VisiData
 
 - `config/shell/`: shell prompt, aliases, input settings, dircolors, and local completions. `config/shell/completions/eslogger.zsh` is the local Zsh completion for Apple’s `eslogger`.