v0.13.1

Re-measures the README token section on 0.13.0 so every figure in it comes from one run, and corrects a claim the new measurement made false. Docs only - no pin, config, hook, or stats changes.

• Every number in the token section now comes from a single measurement. The previous draft quoted 1.79B of subagent volume in one paragraph and 283.7M two lines later. Both were true - the first across all sessions, the second scoped to fable-default ones - and a reader had no way to reconcile them. The section now opens with a two-column table, all sessions against fable-default sessions, with main-session and subagent volume on separate rows, and every later figure states which column it belongs to.
• Corrected a claim the re-measurement falsified. The fable slice grew from 0.7M to 2.1M, and the growth is a model=fable reviewer dispatched deliberately above the session tier - to review 0.13.0 itself. The old text called that slice "the honest remainder" of accidental inheritance, which is now wrong about most of it. It says so instead, and points at the above-tier reporting added in 0.8.0 as the reason a deliberate top-tier dispatch shows up as a decision rather than hiding among at-tier work.
• The scoped headline is 99%, not the 100% quoted before: a fable subagent in a fable session is at tier, not below it, so the deliberate review moved the figure. Left as measured rather than re-scoped to keep the round number.
• Snapshot attribution corrected to v0.13.0; the previous line still credited v0.12.0, which could not have produced the main-session figures beside it.