feat(x): add ScrapeCreators as X/Twitter search backend

One SCRAPECREATORS_API_KEY now covers Reddit, TikTok, Instagram, AND X.
Priority: Bird (free) > xAI API > ScrapeCreators (shared key).

New module scrapecreators_x.py follows the same pattern as tiktok.py.
Updated env.py source routing and last30days.py orchestrator dispatch.
Includes 20 unit tests.

Fixes #55.

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

scripts/lib/env.py

@@ -355,7 +355,8 @@ def get_missing_keys(config: Dict[str, Any]) -> str:
     from . import bird_x
     has_bird = bird_x.is_bird_installed() and bird_x.is_bird_authenticated()
 
-    has_x = has_xai or has_bird
+    has_sc_x = bool(config.get('SCRAPECREATORS_API_KEY'))
+    has_x = has_xai or has_bird or has_sc_x
 
     if has_reddit and has_x and has_web:
         return 'none'
@@ -434,7 +435,7 @@ def validate_sources(requested: str, available: str, include_web: bool = False)
 def get_x_source(config: Dict[str, Any]) -> Optional[str]:
     """Determine the best available X/Twitter source.
 
-    Priority: Bird (free) → xAI (paid API)
+    Priority: Bird (free) → xAI (paid API) → ScrapeCreators (shared key)
 
     Args:
         config: Configuration dict from get_config()
@@ -442,6 +443,7 @@ def get_x_source(config: Dict[str, Any]) -> Optional[str]:
     Returns:
         'bird' if Bird is installed and authenticated,
         'xai' if XAI_API_KEY is configured,
+        'scrapecreators' if SCRAPECREATORS_API_KEY is configured,
         None if no X source available.
     """
     # Import here to avoid circular dependency
@@ -457,6 +459,10 @@ def get_x_source(config: Dict[str, Any]) -> Optional[str]:
     if config.get('XAI_API_KEY'):
         return 'xai'
 
+    # Fall back to ScrapeCreators (same key as Reddit/TikTok/Instagram)
+    if config.get('SCRAPECREATORS_API_KEY'):
+        return 'scrapecreators'
+
     return None
 
 
@@ -559,11 +565,15 @@ def get_x_source_status(config: Dict[str, Any]) -> Dict[str, Any]:
     bird_status = bird_x.get_bird_status()
     xai_available = bool(config.get('XAI_API_KEY'))
 
+    sc_available = bool(config.get('SCRAPECREATORS_API_KEY'))
+
     # Determine active source
     if bird_status["authenticated"]:
         source = 'bird'
     elif xai_available:
         source = 'xai'
+    elif sc_available:
+        source = 'scrapecreators'
     else:
         source = None
 
@@ -573,5 +583,6 @@ def get_x_source_status(config: Dict[str, Any]) -> Dict[str, Any]:
         "bird_authenticated": bird_status["authenticated"],
         "bird_username": bird_status["username"],
         "xai_available": xai_available,
+        "scrapecreators_available": sc_available,
         "can_install_bird": bird_status["can_install"],
     }