Polish: clearer errors, corrected docstrings, setuptools pin

- insert/upsert into a name that is actually a view now shows a
  clean error instead of a traceback
- db.view() on a name that is a table now says so in its error
- Database.__getitem__ docstring documents that views are returned
  for view names; hash_id docstring corrected (it is a column name,
  not a boolean)
- Registering two migrations with the same name in one set now
  raises ValueError at registration time instead of executing both
  and failing with IntegrityError at apply time
- build-system requires setuptools>=77, needed for the PEP 639
  license expression

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UnLnhsH25Nnv7LHhekUfPd

tests/test_cli_insert.py

@@ -615,3 +615,16 @@ def test_insert_csv_headers_only(tmpdir):
     # Table should not exist since there were no data rows
     db = Database(db_path)
     assert not db["data"].exists()
+
+
+def test_insert_into_view_errors(tmpdir):
+    db_path = str(tmpdir / "test.db")
+    db = Database(db_path)
+    db["t"].insert({"id": 1})
+    db.create_view("v", "select * from t")
+    db.close()
+    result = CliRunner().invoke(
+        cli.cli, ["insert", db_path, "v", "-"], input='{"id": 2}'
+    )
+    assert result.exit_code == 1
+    assert result.output.strip() == "Error: Table v is actually a view"