Refactor Pushgate CLI to integrate pre-push hook and remove separate push command (#70)

- Updated documentation to reflect changes in the workflow, emphasizing the integration of Pushgate with Git's pre-push hook.
- Removed the `push` command from the CLI, consolidating functionality into the `pre-push` command.
- Eliminated the `push-args.ts` and `push.ts` modules, simplifying the codebase by removing unnecessary abstractions related to push operations.
- Adjusted the `skip-controls.ts` to remove the `buildGitPushArgs` function, as it is no longer needed.
- Deleted tests related to the `push` command and its associated functionality, ensuring the test suite reflects the current state of the codebase.
- Updated existing tests to verify the absence of the `push` command and ensure proper handling of the new workflow.

Co-authored-by: dbrosio3 <daniel.brosio@rootstrap.com>

Author: dbrosio3

README.md

@@ -31,10 +31,8 @@ git push
 ```
 
 `git push` stays the main entry point. Pushgate plugs into it through the
-installed `pre-push` hook; `pushgate push` is an optional friendly wrapper for
-the same workflow. For long interactive runs, such as warning prompts plus local
-AI review, `pushgate push` runs the local Pushgate preflight before opening the
-native Git push and then invokes `git push --no-verify` after Pushgate passes.
+installed `pre-push` hook, so developers keep the usual Git workflow while
+local checks and AI review run before the push proceeds.
 
 Local deterministic checks can block a push. Warning results require an explicit yes/no confirmation before the push continues. Local AI supports `blocking`, `advisory`, and `off` modes; `blocking` is the default, matching the review gate shown above. CI and PR checks remain the final enforcement point for policy that must survive local hook skips.
 
@@ -229,15 +227,6 @@ git -c pushgate.skip-ai-check=true push
 git -c pushgate.skip-all-checks=true push
 ```
 
-The optional wrapper maps friendly flags to the same one-push config. It also
-runs Pushgate locally before the native network push, so long checks and warning
-prompts do not hold an already-open Git remote session idle:
-
-```bash
-pushgate push --skip-ai-check
-pushgate push --skip-all-checks
-```
-
 ## Runner overrides
 
 The installed hook resolves the Pushgate runner in this order: