Initial commit: CI Agent competitive-intelligence monitoring app

FastAPI + Celery + Next.js + Postgres/Redis app with company monitoring,
source collection, LLM-based change analysis, enrichment, and account
security (Turnstile, escalating lockout, email verification).

apps/api/tests/unit/test_text_diff.py

@@ -0,0 +1,34 @@
+from __future__ import annotations
+
+from app.change_detection.text_diff import bounded_text_diff
+
+
+def test_identical_text_has_zero_diff_ratio():
+    text = "Acme Corp builds electric trucks.\nWe are hiring engineers."
+    result = bounded_text_diff(text, text)
+    assert result.diff_ratio == 0.0
+    assert result.is_identical is True
+
+
+def test_changed_text_has_nonzero_diff_ratio_and_captures_lines():
+    previous = "Acme Corp builds gasoline trucks.\nContact us for a quote."
+    current = "Acme Corp builds electric trucks.\nContact us for a quote."
+    result = bounded_text_diff(previous, current)
+    assert result.diff_ratio > 0.0
+    assert any("electric" in line for line in result.added_lines)
+    assert any("gasoline" in line for line in result.removed_lines)
+
+
+def test_noise_only_changes_do_not_register_as_a_diff():
+    previous = "About us.\nUpdated: 2026-01-01 10:00\nWe build trucks."
+    current = "About us.\nUpdated: 2026-06-15 14:30\nWe build trucks."
+    result = bounded_text_diff(previous, current)
+    assert result.diff_ratio == 0.0
+
+
+def test_diff_is_bounded_in_size():
+    previous = "\n".join(f"line {i} original" for i in range(200))
+    current = "\n".join(f"line {i} changed" for i in range(200))
+    result = bounded_text_diff(previous, current)
+    assert len(result.added_lines) <= 40
+    assert len(result.removed_lines) <= 40