Improve URL handling across explore flow and scope sessions per workspace

[DenysKuchma]

• Fixes false-positive navigation success when the browser ends up on a different origin with the same path.
• Scopes --session storage to the selected workspace instead of reusing a shared root output/session.json.
• Normalizes URL handling across the explore flow to prefer fullUrl when available, which improves behavior on apps using prefixed routes and SPA
  navigation.
• Makes research and deep analysis more resilient by falling back gracefully when expandable discovery/selection fails.
• Improves planner guidance so generated scenarios rely less on invented routes, messages, and hidden prerequisites.
• Improves pilot guidance so equivalent success states are accepted even when the UI does not match one narrow expected micro-signal.
• Enriches session analysis output with checked expectations, remaining expectations, visited URLs, verification details, and recent notes.
• Adds unit coverage for the navigation origin guard.