Rename to stealergram, add pyproject.toml, purge em-dashes

- Rename project to stealergram throughout
- Add pyproject.toml (replaces requirements.txt split, folds pytest.ini)
- Replace all em-dashes with hyphens across all source files

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

tests/test_processor.py

@@ -1,5 +1,5 @@
 """
-Tests for core/processor.py — archive extraction and line-by-line search.
+Tests for core/processor.py - archive extraction and line-by-line search.
 
 No Telegram deps, no async. Tests create real archive fixtures in tmp_path
 so process_file's cleanup guarantee can be verified against actual disk state.
@@ -60,7 +60,7 @@ class TestSearchFile:
         assert search_file(f, patterns) == ["testcorp.com|user|pass"]
 
     def test_handles_encoding_errors_gracefully(self, tmp_path, patterns):
-        """Combo files are often messy — invalid bytes must not crash the search."""
+        """Combo files are often messy - invalid bytes must not crash the search."""
         f = tmp_path / "combo.txt"
         f.write_bytes(
             b"testcorp.com|user1|pass\n"
@@ -81,7 +81,7 @@ class TestSearchFile:
         assert len(hits) == 2
 
 
-# ─── process_file — plain .txt ────────────────────────────────────────────────
+# ─── process_file - plain .txt ────────────────────────────────────────────────
 
 class TestProcessFilePlainText:
     def test_returns_hits(self, tmp_path, patterns):
@@ -104,7 +104,7 @@ class TestProcessFilePlainText:
         assert not f.exists()
 
 
-# ─── process_file — .zip extraction ──────────────────────────────────────────
+# ─── process_file - .zip extraction ──────────────────────────────────────────
 
 class TestProcessFileZip:
     def _make_zip(self, tmp_path: Path, content: str, filename="content.txt") -> Path:
@@ -155,7 +155,7 @@ class TestProcessFileZip:
         assert len(hits) == 2
 
 
-# ─── process_file — nested archives ──────────────────────────────────────────
+# ─── process_file - nested archives ──────────────────────────────────────────
 
 class TestProcessFileNested:
     def test_nested_zip_is_recursed(self, tmp_path, patterns):
@@ -177,7 +177,7 @@ class TestProcessFileNested:
         assert not (tmp_path / "outer").exists()
 
 
-# ─── process_file — password-protected .7z ───────────────────────────────────
+# ─── process_file - password-protected .7z ───────────────────────────────────
 
 class TestProcessFile7zPassword:
     def test_unlocks_with_correct_password(self, tmp_path, patterns, monkeypatch):
@@ -218,6 +218,6 @@ class TestProcessFile7zPassword:
             z.write(txt, "content.txt")
         txt.unlink()
 
-        # No hits — archive could not be opened
+        # No hits - archive could not be opened
         hits = process_file(szf, patterns)
         assert hits == []