refactor(capture): extract workflow logic with proper separation of concerns

- Add workflow.py with phase-specific result types:
  - BrowserCheckResult: browser installation check
  - ConnectivityResult: connectivity check
  - AuthResult: authentication detection
  - CaptureResult: capture operation result
- CaptureWorkflowResult composes phase results with convenience properties
- cli/capture.py now thin CLI layer using workflow functions
- Add comprehensive tests for all workflow types and functions (35 tests)

This design makes each type testable in isolation and clarifies
which fields are valid in which phase.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: kwschulz

src/har_capture/capture/__init__.py

@@ -9,6 +9,8 @@
     - CaptureOptions: Options for filtering (fonts, images, media)
     - check_playwright: Check if Playwright is available
     - install_playwright: Install Playwright and browser
+    - CaptureWorkflowResult: Result dataclass from workflow
+    - run_capture_workflow: Run the complete capture workflow
 """
 
 from __future__ import annotations
@@ -30,6 +32,18 @@
     install_browser_deps,
     install_playwright,
 )
+from har_capture.capture.workflow import (
+    AuthResult,
+    BrowserCheckResult,
+    CaptureWorkflowResult,
+    ConnectivityResult,
+    check_auth_phase,
+    check_browser_phase,
+    check_connectivity_phase,
+    run_capture_phase,
+    run_capture_workflow,
+)
+from har_capture.capture.workflow import CaptureResult as WorkflowCaptureResult
 
 __all__ = [
     # Core capture
@@ -46,4 +60,15 @@
     "install_playwright",
     "install_browser",
     "install_browser_deps",
+    # Workflow orchestration
+    "CaptureWorkflowResult",
+    "BrowserCheckResult",
+    "ConnectivityResult",
+    "AuthResult",
+    "WorkflowCaptureResult",
+    "check_browser_phase",
+    "check_connectivity_phase",
+    "check_auth_phase",
+    "run_capture_phase",
+    "run_capture_workflow",
 ]