Resolve all ruff lint, formatting, and mypy type checking errors across the codebase.

• E501 line-too-long (protocol.py, screens.py): Rewrap long lines — split debug call args, extract format string to local, move inline comment above code
• UP035 + TC003 (tui/app.py): Import Awaitable from collections.abc and move into TYPE_CHECKING block
• TC002 (tui/auth_screen.py): Move ComposeResult into TYPE_CHECKING block (only used in annotations, from __future__ import annotations is active)
• I001 (tui/app.py): Fix import sort order as a side effect of the above
• ruff format: Applied ruff format . across all 19 files that were not conforming to the canonical formatter style (source and test files)
• mypy arg-type (b2c_login.py): Wrap url string with yarl.URL() for filter_cookies which expects a URL type
• mypy arg-type (heat_mode_screen.py, flame_speed_screen.py, fire_select_screen.py): Annotate Button variant variables with ButtonVariant type alias to satisfy the Literal expectation
• mypy union-attr (tui/app.py): Add None guard for sys.__stderr__ before accessing .fileno(), .buffer, and .flush()

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