Fix module path mismatch for go install

Resolve GitHub issue #2 by aligning the Go module identity with the repository path so  works.

Changes made:
- Updated go.mod module path from github.com/rcarmo/webterm-go-port to github.com/rcarmo/webterm.
- Updated all internal import references to the new module path.
- Updated version ldflags in Makefile and Dockerfile to use github.com/rcarmo/webterm/webterm.Version.
- Added README quick-install section documenting the  command.

Validation:
- Ran make check successfully after the rename/import updates.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

README.md

@@ -24,6 +24,12 @@ This repository is the Go port of the original Python implementation, which is p
 
 ## Install
 
+### Quick install
+
+```bash
+go install github.com/rcarmo/webterm/cmd/webterm@latest
+```
+
 ### Build from source
 
 ```bash