Fix overlapping text in wide terminals

[sj26]

Why

When interactive playback advances between paragraphs, the terminal renderer moves up from the status line but keeps its horizontal cursor position. It then clears and rewrites the completed paragraph from that offset, leaving the old text on the left and producing duplicated, overlapping output—especially visibly in wide terminals.

What

Return the cursor to column zero before clearing and committing the completed paragraph. Add a focused regression test for the emitted cursor sequence so future changes cannot reintroduce the offset rendering.

Validation:

• .venv/bin/python -m unittest discover -s tests -v — 1 test passed
• .venv/bin/python -m py_compile aloud.py tests/test_terminal_rendering.py — passed
• git diff --check origin/main...HEAD — passed
• PTY + terminal-emulator reproduction at 80 and 240 columns: baseline rendered the committed heading twice at both widths; fixed branch rendered it once with the next paragraph in a clean region.