feat: add user-tweets command to fetch tweets from a user's profile

Adds new CLI command to fetch tweets from any user's profile timeline.

Usage:
  bird user-tweets @username [-n count] [--pages N] [--json]

Features:
- GraphQL UserByScreenName for username → userId resolution
- Cursor-based pagination with configurable delay (rate-limit safe)
- Hard cap of 10 pages to prevent abuse
- Input validation via normalizeHandle()

Includes 17 unit tests and live smoke test.

Co-authored-by: Christian Catalan <[email protected]>

src/lib/twitter-client-features.ts

@@ -232,6 +232,46 @@ export function buildHomeTimelineFeatures(): Record<string, boolean> {
   });
 }
 
+export function buildUserTweetsFeatures(): Record<string, boolean> {
+  return applyFeatureOverrides('userTweets', {
+    rweb_video_screen_enabled: false,
+    profile_label_improvements_pcf_label_in_post_enabled: true,
+    responsive_web_profile_redirect_enabled: false,
+    rweb_tipjar_consumption_enabled: true,
+    verified_phone_label_enabled: false,
+    creator_subscriptions_tweet_preview_api_enabled: true,
+    responsive_web_graphql_timeline_navigation_enabled: true,
+    responsive_web_graphql_skip_user_profile_image_extensions_enabled: false,
+    premium_content_api_read_enabled: false,
+    communities_web_enable_tweet_community_results_fetch: true,
+    c9s_tweet_anatomy_moderator_badge_enabled: true,
+    responsive_web_grok_analyze_button_fetch_trends_enabled: false,
+    responsive_web_grok_analyze_post_followups_enabled: true,
+    responsive_web_jetfuel_frame: true,
+    responsive_web_grok_share_attachment_enabled: true,
+    responsive_web_grok_annotations_enabled: false,
+    articles_preview_enabled: true,
+    responsive_web_edit_tweet_api_enabled: true,
+    graphql_is_translatable_rweb_tweet_is_translatable_enabled: true,
+    view_counts_everywhere_api_enabled: true,
+    longform_notetweets_consumption_enabled: true,
+    responsive_web_twitter_article_tweet_consumption_enabled: true,
+    tweet_awards_web_tipping_enabled: false,
+    responsive_web_grok_show_grok_translated_post: true,
+    responsive_web_grok_analysis_button_from_backend: true,
+    creator_subscriptions_quote_tweet_preview_enabled: false,
+    freedom_of_speech_not_reach_fetch_enabled: true,
+    standardized_nudges_misinfo: true,
+    tweet_with_visibility_results_prefer_gql_limited_actions_policy_enabled: true,
+    longform_notetweets_rich_text_read_enabled: true,
+    longform_notetweets_inline_media_enabled: true,
+    responsive_web_grok_image_annotation_enabled: true,
+    responsive_web_grok_imagine_annotation_enabled: true,
+    responsive_web_grok_community_note_auto_translation_is_enabled: false,
+    responsive_web_enhance_cards_enabled: false,
+  });
+}
+
 export function buildFollowingFeatures(): Record<string, boolean> {
   return applyFeatureOverrides('following', {
     rweb_video_screen_enabled: true,