feat: implement complete tree-sitter-shellspec grammar with comprehensive testing

- Add full ShellSpec grammar extending tree-sitter-bash
- Support all ShellSpec constructs: Describe, Context, It, hooks, utilities
- Include Data block parsing with statements and argument styles
- Add 61 comprehensive test cases covering real-world patterns
- Implement optimized GitHub workflows with CI/CD automation
- Configure complete development tooling (linting, formatting, pre-commit)
- Add comprehensive documentation and contribution guidelines
- Optimize grammar conflicts to zero warnings
- Support editor integration for Neovim, VS Code, Emacs

Breaking Changes:
- Initial release, no previous API to break

BREAKING CHANGE: Initial implementation of tree-sitter-shellspec grammar

# Conflicts:
#	.github/workflows/codeql.yml
#	.github/workflows/pr-lint.yml
#	.pre-commit-config.yaml

# Conflicts:
#	.github/workflows/pr-lint.yml

# Conflicts:
#	.github/workflows/pr-lint.yml

test/spec/09.subject_spec.sh

@@ -0,0 +1,117 @@
+#shellcheck shell=sh
+
+Describe 'subject example'
+  Describe 'stdout'
+    foo() { echo "ok"; }
+
+    It 'uses the stdout as the subject'
+      When call foo
+      The stdout should eq "ok"
+    End
+
+    It 'has an alias "output"'
+      When call foo
+      The output should eq "ok"
+    End
+
+    Describe 'with entire'
+      It 'does not remove last LF'
+        When call foo
+        The entire output should eq "ok${SHELLSPEC_LF}"
+      End
+
+      # Without "entire", the "output" subject act as like
+      # the command substitution.
+      #
+      # For example "echo" outputs a newline at the end.
+      # In spite of that `[ "$(echo ok)" = "ok" ]` will success.
+      # Because the command substitution removes trailing newlines.
+      #
+      # The "entire output" subject does not remove trailing newlines.
+    End
+  End
+
+  Describe 'stderr'
+    foo() { echo "err" >&2; }
+
+    It 'uses the stderr as the subject'
+      When call foo
+      The stderr should eq "err"
+    End
+
+    It 'has an alias "error"'
+      When call foo
+      The error should eq "err"
+    End
+
+    Describe 'with entire'
+      It 'does not remove last LF'
+        When call foo
+        The entire error should eq "err${SHELLSPEC_LF}"
+      End
+    End
+  End
+
+  Describe 'status'
+    foo() { return 123; }
+
+    It 'uses the status as the subject'
+      When call foo
+      The status should eq 123
+    End
+  End
+
+  Describe 'variable'
+    foo() { var=456; }
+
+    It 'uses the variable as the subject'
+      When call foo
+      The variable var should eq 456
+    End
+  End
+
+  Describe 'value'
+    foo() { var=789; }
+
+    It 'uses the value as the subject'
+      When call foo
+      The value "$var" should eq 789
+    End
+  End
+
+  Describe 'function'
+    foo() { echo "ok"; }
+
+    It 'is alias for value'
+      The function "foo" should eq "foo"
+      The "foo()" should eq "foo" # shorthand for function
+    End
+
+    It 'uses with result modifier'
+      The result of "foo()" should eq "ok"
+    End
+  End
+
+  Describe 'path'
+    # Path helper defines path alias.
+    Path hosts-file='/etc/hosts'
+
+    It 'uses the resolved path as the subject'
+      The path hosts-file should eq '/etc/hosts'
+    End
+
+    It 'has an alias "file"'
+      Path hosts='/etc/hosts'
+      The file hosts should eq '/etc/hosts'
+    End
+
+    It 'has an alias "dir"'
+      Path target='/foo/bar/baz/target'
+      The dir target should eq '/foo/bar/baz/target'
+    End
+
+    It 'is same as value if path alias not found. but improve readability'
+      The path '/etc/hosts' should eq '/etc/hosts'
+    End
+  End
+End