ci: Add GitHub Actions workflows for automated testing and linting

Added 3 workflow files following FTNetworkTracer's modern pattern:

- test.yml: Runs swift build and swift test on macOS for every push to main and all PRs
  - Path-filtered to run only when Swift files or package configuration changes
  - Uses actions/checkout@v4 (latest stable)
  - Verbose output for debugging

- lint-swift.yml: Runs SwiftLint in strict mode on all PRs
  - Enforces code quality standards
  - Zero tolerance for warnings
  - Path-filtered for efficiency

- lint-workflows.yml: Validates workflow files using actionlint
  - Catches workflow syntax errors and best practice violations
  - Includes problem matcher for IDE integration

All workflows use path-based filtering for efficiency and follow Futured's established patterns from FTNetworkTracer and FTAPIKit repositories.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: Šimon Šesták

.github/actionlint-matcher.json

@@ -0,0 +1,17 @@
+{
+  "problemMatcher": [
+    {
+      "owner": "actionlint",
+      "pattern": [
+        {
+          "regexp": "^(?:\\x1b\\[\\d+m)?(.+?)(?:\\x1b\\[\\d+m)?:(?:\\x1b\\[\\d+m)?(\\d+)(?:\\x1b\\[\\d+m)?:(?:\\x1b\\[\\d+m)?(\\d+)(?:\\x1b\\[\\d+m)?: (?:\\x1b\\[\\d+m)?(.+?)(?:\\x1b\\[\\d+m)? \\[(.+?)\\]$",
+          "file": 1,
+          "line": 2,
+          "column": 3,
+          "message": 4,
+          "code": 5
+        }
+      ]
+    }
+  ]
+}

.github/workflows/lint-swift.yml

@@ -0,0 +1,26 @@
+name: Lint Swift
+
+on:
+  pull_request:
+    branches:
+      - '*'
+    paths:
+      - '**/*.swift'
+      - 'Package.swift'
+      - 'Package.resolved'
+      - '.swiftlint.yml'
+      - '.github/workflows/lint-swift.yml'
+
+jobs:
+  swiftlint:
+    name: SwiftLint
+    runs-on: macos-latest
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Install SwiftLint
+      run: brew install swiftlint
+
+    - name: Run SwiftLint
+      run: swiftlint lint --strict

.github/workflows/lint-workflows.yml

@@ -0,0 +1,30 @@
+name: Lint Workflows
+
+on:
+  pull_request:
+    branches:
+      - '*'
+    paths:
+      - '.github/workflows/*.yml'
+      - '.github/actionlint-matcher.json'
+
+jobs:
+  actionlint:
+    name: actionlint
+    runs-on: ubuntu-latest
+    timeout-minutes: 30
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Download actionlint
+      id: get_actionlint
+      run: bash <(curl https://raw.githubusercontent.com/rhysd/actionlint/main/scripts/download-actionlint.bash)
+      shell: bash
+
+    - name: Register problem matcher
+      run: echo "::add-matcher::.github/actionlint-matcher.json"
+
+    - name: Run actionlint
+      run: ${{ steps.get_actionlint.outputs.executable }} -color
+      shell: bash

.github/workflows/test.yml

@@ -0,0 +1,36 @@
+name: Test
+
+on:
+  push:
+    branches:
+      - main
+    paths:
+      - '**/*.swift'
+      - 'Package.swift'
+      - 'Package.resolved'
+      - '.github/workflows/test.yml'
+  pull_request:
+    branches:
+      - '*'
+    paths:
+      - '**/*.swift'
+      - 'Package.swift'
+      - 'Package.resolved'
+      - '.github/workflows/test.yml'
+
+jobs:
+  macos:
+    name: macOS
+    runs-on: macos-latest
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Swift version
+      run: swift --version
+
+    - name: Build
+      run: swift build -v
+
+    - name: Run tests
+      run: swift test -v