feat: native SSH command execution with async-ssh2-tokio (#250)

* feat: implement remote commands execution via ssh

* wip

* feat: execute SSH commands and stream output directly

* style: fix md format

* style: apply automated fixes

* fix: pass quiet flag to connect to suppress spinner

* refactor: load config only once

* chore: add .gitattributes

* test: add e2e test using ssh server

* test: add tests

* chore: remove biwa.toml

* refactor: remove duplicate test and update spinner

* refactor: extract spinner into crate-level ui module

* refactor(ssh): split execute_command into build_command + run_command, DRY stream writing

* chore: remove biwa.toml

* chore: remove test file

* chore(.gitattributes): fix dir

* style: autofix clippy

* style: apply automated fixes

* chore(clippy): disable multiple_crate_versions

* refactor: fix clippy warnings

* refactor: fix clippy warnings

* style: apply automated fixes

* refactor: replace ENV_MUTEX with serial_test for env-mutating tests

* chore(deny): makee config strict

* fix: rename connect() parameter silent -> quiet for spinner suppression

* chore: lower visibility of cli subcommands and create_spinner

* refactor: replace unnecessary pub(crate) and pub with private/pub(super)

* refactor: remove missed pub declarations on internal methods

* feat: support encrypted ssh keys

---------

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

Author: risu729

.gitattributes

@@ -0,0 +1,4 @@
+* text=auto
+biwa.usage.kdl linguist-generated
+schema/config.json linguist-generated
+docs/src/cli/** linguist-generated

.github/workflows/ci.yaml

@@ -26,6 +26,16 @@ jobs:
       contents: read # for checkout
       id-token: write # for codecov
 
+    services:
+      ssh-server:
+        image: lscr.io/linuxserver/openssh-server@sha256:fdd9783e0fa4c52592c8405765c5de04dcf657db1b4d6ab073c14c4b998ca1fa
+        ports:
+          - 2222:2222
+        env:
+          USER_NAME: testuser
+          USER_PASSWORD: password123
+          PASSWORD_ACCESS: "true"
+
     steps:
       - name: Checkout
         uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2