add usajobs.py cli with full api, filter, display, and export pipeline

milestones 1-6 complete: fetch/cache from data.usajobs.gov, local filters
for pay plan/grade/salary/location, rich table output, questionary selection
prompt, and org-mode export. key field mappings resolved from live api
inspection (JobGrade[0].Code for pay plan, UserArea.Details for grades and
clearance, city-part location matching due to api returning full state names).

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

.gitignore

@@ -0,0 +1,31 @@
+.env
+.cache/
+exports/
+*.sqlite
+*.sqlite3
+__pycache__/
+.pytest_cache/
+.venv/
+venv/
+dist/
+build/
+*.pyc
+
+# android
+android/.gradle/
+android/local.properties
+android/**/build/
+android/captures/
+*.apk
+*.aab
+*.hprof
+
+# ide
+.idea/
+.vscode/
+*.iml
+
+# os and emacs
+.DS_Store
+Thumbs.db
+/archive