mode-economics: add an ASF-scoped LLMAO section

[potiuk]

Follow-up to #1260 and #1261.

What

Give docs/mode-economics.md an ASF-scoped section carrying the LLMAO measurements from #1261, rather than folding those numbers into the page's main tables.

Why scoped rather than inline

LLMAO is available to ASF committers only. Numbers that most readers of a public page cannot act on do not belong in the tables they read first — they invite the reasonable-but-wrong conclusion that these are costs anyone can obtain.

Magpie already solves this shape elsewhere: the framework is organisation-agnostic and carries organisation-specific material in clearly-marked sections, with organizations/ASF/ as the ASF instance of it. This should follow the same pattern rather than inventing a new one.

The page's own Long-term: the ASF inference endpoint section already anticipates this content:

As pilot adopters accumulate real usage data, this page will be updated with observed ranges rather than theoretical estimates, so the endpoint sizing argument rests on evidence.

So this is filling an existing promise, not adding a new claim.

Shape

• An ASF-scoped section, marked as such, holding per-skill token and wall-clock figures per LLMAO model.
• Explicit that access requires an ASF committer PAT, so a reader outside the ASF knows immediately whether this applies to them.
• Figures labelled with the date and model version measured. These are pilot numbers on a service under active capacity work; an undated figure will be quietly wrong within weeks.
• The main tables stay vendor-comparable and untouched.

Done when

• The section exists, is populated from Measure Magpie skill economics against LLMAO's three models #1261, and is unambiguously marked ASF-only.
• Nothing in the general tables implies LLMAO numbers apply to a non-ASF reader.
• check-doc-sync and the token-count hook pass — this page is partly generated, so hand-edits must land outside the generated block.