enhancement: acp_status drilldown cannot reach the newest messages — sort:time is ascending-only, slice(0,limit) has no offset/reverse

[Tyan66666]

Problem

acp_status drilldown (scope:"uncompressed" + view:"messages") with sort:"time" always starts from the OLDEST message. With the default limit: 30 (and any limit < total message count), the NEWEST messages are unreachable — there is no offset, reverse, or descending-time sort option.

Mechanism (dist/index.js 0.0.29)

// renderMessageDrilldown
if (sort === "time") filtered.sort((a, b) => a.index - b.index); // ascending only
...
const shown = filtered.slice(0, limit); // head-only, no pagination

collectVisible assigns index = array position (0-based, ascending), so sort:"time" shows oldest-first and slice(0, limit) truncates the tail. Any limit < total count hides the newest messages.

Why it matters

• The model cannot locate the newest (often largest, just-executed) tool outputs without a message-stream ref tag.
• In billion-context-pi the model sees per-message <acp> ref tags injected into the message stream (src/messages.ts patchRefTag), so drilldown is only an auxiliary view there. Hosts WITHOUT such tags (e.g. billion-context-dsh, decision: no <acp> tags, seq-is-the-ref) rely on drilldown as the ONLY message-location entry — the head-only behavior is amplified into a real gap.
• Same limitation applies to sort:"size"/sort:"tool" (head limit rows of the sorted order) — large tool outputs from the tail of the conversation cannot be seen unless the model knows the tool name and uses tool:"X" + sort:"size".

Requested change

Add a way to reach the tail of the list, any of:

1. reverse: true option (flip the sort order after sorting)
2. offset: number option (pagination)
3. sort:"time-desc" (or make sort:"time" descending and add "time-asc")

Minimal and backwards-compatible; benefits both pi and DSH hosts.

Context

Tracking issue in our host repo: Tyan66666/billion-context-dsh#46