insights: an all-wins profit factor reads "—" (unknown) on Rules but "Infinity" in the CLI #979

Found while reviewing PR #975 (round 1, O2). This is not new: it was there before that PR.

What happens. A rule with winning trades and no losing ones has an infinite profit factor (stats.summarize returns Decimal("Infinity") when gross loss is 0 and gross profit is above 0).

• keel insights summary prints profit_factor=Infinity.
• The Rules view shows "—" with state unknown, because payload.ratio() turns any non-finite value into absent().
• The gate card's realized_rr on an all-wins record shows "—" too. The CLI says rr=n/a (no losses yet) there.

Why it matters. This is the reverse of #965. Instead of an unknown shown as zero, a known value (no losses so far) is shown as unknown, and the page and the CLI disagree.

Fix (display only).

• On the page, render an infinite profit factor as something like "∞ (no losses yet)" with a neutral state, not unknown.
• In the CLI, pick one wording for both places, for example profit_factor=n/a (no losses yet) to match rr.
• Gate verdicts are unaffected: check_floors reads the engine's own values.

Test. An all-wins record's profit factor reads the same reason on the page and in the CLI, and its page state is not unknown.