fix(e2e): resolve blocklist import test failures

auth.resource:
- add Login Via HTTP keyword for RequestsLibrary auth (CSRF-aware)
- fix session_duration_minutes type: bare int → ${60}
- add Process library import to common.resource

03_blocklist_import.robot:
- fix selector to button[data-testid] (was matching all buttons)
- use GET/POST On Session with auth session for blocklist API calls
- fix log response key: entries → items
- fix enabled=true → ${TRUE} for boolean type
- fix ${len(sources)} → Get Length keyword
- make Ensure Blocklist Source Exists accept session argument
- replace strict error assertion with specific error banner check
- add graceful Terminate Process teardown

02_ban_records.robot:
- add Process library import

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

e2e/resources/common.resource

@@ -1,6 +1,7 @@
 *** Settings ***
 Library    Browser
 Library    RequestsLibrary
+Library    Process
 
 *** Variables ***
 ${FRONTEND_URL}    http://localhost:5173