ci: extend mypy to openfusion/cli.py, fix the type errors it finds

[shrdgn]

What & why

openfusion/cli.py — the CLI/REPL entrypoint, and at 510+ lines the largest hand-written
module in openfusion/ — was the only module in the package excluded from mypy, in both
pyproject.toml's [tool.mypy] (exclude = ["openfusion/cli\\.py"]) and the CI workflow's
own --exclude openfusion/cli.py flag. Running mypy on it directly (as CI never does)
immediately surfaces two real issues, both in _chat_turn's Rich-rendering branch:

cli.py:238: error: Name "content" already defined on line 218  [no-redef]
cli.py:239: error: "object" has no attribute "status"  [attr-defined]
cli.py:254/257/266: error: "object" has no attribute "print"  [attr-defined]

1. console: object | None = None (the function's third param) is typed as bare object
   instead of rich.console.Console | None, which defeats attribute checking on every
   console.status(...)/console.print(...) call in the branch that uses it. A real typo in
   one of those calls (e.g. a renamed Rich API) would go uncaught by mypy and only surface when
   someone actually ran openfusion chat interactively.
2. A content variable is assigned in the plain-text branch (content, _ = majority_vote(panel)
   at what's now line 219) and then re-declared with an explicit str | None annotation in the
   Rich-rendering branch below it (line 238) — a redefinition-with-conflicting-type mypy flags
   even though the two branches are mutually exclusive at runtime (the first branch always
   returns before the second is reached).

Fix

• Added a TYPE_CHECKING-only from rich.console import Console import and typed the param
  as Console | None. rich is already a hard (non-optional) dependency
  (pyproject.toml's dependencies), and the file already does from __future__ import annotations, so this adds zero runtime import cost — the existing lazy from rich.console import Console inside run_chat (kept for CLI startup latency on non-chat subcommands) is
  untouched.
• Renamed the Rich-rendering branch's content to answer to remove the redefinition.
• Removed the cli.py exclude from both pyproject.toml and .github/workflows/ci.yml's
  mypy step.

Not touched: [tool.coverage.run]'s separate omit = [..., "openfusion/cli.py"] — that's
about pytest --cov, not mypy, and its own comment explains a different, still-valid
rationale (TTY/stdin mocking noise) unrelated to this change.

How it was tested

• ruff check . passes
• pytest -q passes (490 passed, no live network — no new tests needed, this is a
  type-only change with no runtime behavior difference)
• mypy openfusion/ --ignore-missing-imports --disable-error-code import-untyped (the
  exact CI invocation, now scope-widened) — Success: no issues found in 25 source files
• Docs updated — not needed, no config/request-surface/defaults changed
• No secrets, prompts, or response bodies added to logs or metrics
• Bench number — not applicable, no model-call behavior changed

Notes for reviewers

Found via an automated repo-review scheduled task; verified by hand by running mypy against
cli.py directly (bypassing the exclude) and confirming it was the only module in
openfusion/ carrying one, in both places it's configured.

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Generated by Claude Code