Auto-load detection library from S1 API, improve coverage map accuracy

- Fetch detection library rules from platform-rules API at startup (falls
  back to extracted.json); adds Sync Detection Library button for refresh
- Parser column simplified to ✓ Parsed / ✗ Not Parsed
- Detection counts now use library rules only (exclude custom STAR rules)
- Add close-match suggestions for dataSource.name mismatches (e.g. CloudTrail
  → AWS CloudTrail, Microsoft 365 Collaboration → Microsoft O365)
- Exclude SentinelOne Ranger AD from coverage map (native S1 source)
- Add success feedback banners to Load SDL Parsers and Sync Library buttons
- Remove rule_counts.json manual override; extracted.json is source of truth
- Remove Load Detections button; rules auto-import on backend startup
- Add get_account_id() and get_platform_rules() to s1_client

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/routers/settings.py

@@ -15,9 +15,6 @@ FIELDS = [
     {"key": "SDL_XDR_URL",          "label": "SDL XDR URL",                   "secret": False, "placeholder": "https://xdr.us1.sentinelone.net"},
     {"key": "SDL_LOG_READ_KEY",     "label": "SDL Log Read Key",              "secret": True,  "placeholder": "1DnK0Y4e..."},
     {"key": "ANTHROPIC_API_KEY",    "label": "Anthropic API Key",             "secret": True,  "placeholder": "sk-ant-..."},
-    {"key": "STAR_LIBRARY_ONLY",    "label": "STAR Rules — Library Only",     "secret": False, "placeholder": "true",
-     "type": "select", "options": ["true", "false"],
-     "hint": "true = load only SentinelOne Library rules (@sentinelone.com creators). false = include custom tenant rules as well."},
 ]
 
 FIELD_KEYS = {f["key"] for f in FIELDS}