Numeric flags accept anything and fail silently as NaN

[royalpinto007]

--max, --max-tool and --price all go straight through Number(...) with no check:

const price = Number(flag("--price", 3));
maxTokens: flag("--max", null) ? Number(flag("--max", null)) : null,

tokencut payload.json --compact --max abc gives maxTokens: NaN. The trim loop condition is total > NaN, which is always false, so the command reports "saved 0 tokens" and exits 0. It looks like the payload was already under budget.

--price abc is worse: every cost in the output becomes $NaN.

Acceptance

• A non-numeric or negative value for any of the three flags exits non-zero with a message naming the flag and what it got
• --max 0 is still accepted (a legitimate, if extreme, budget)
• Tests cover a bad value for each flag

Good first issue: one small helper and three call sites.

[vsolano9]

I’m working on this. I’ll add one finite non-negative numeric parser for --max, --max-tool, and --price; reject missing, non-numeric, non-finite, and negative values with the exact flag/value in stderr; preserve --max 0; and test the real CLI process.