fix: sort milestones ascending by ID in browser UI

[raincrossgazette]

Problem

The milestones page in the browser UI sorts milestone cards by ID descending (newest first). This means a project with milestones created in phase order ends up displaying them in reverse — e.g. Phase 9 (m-6) appears at the top, then Phase 7 (m-4), then Phase 8 (m-5).

The comment in the code itself acknowledges the intent: "IDs are sequential m-0, m-1, etc." — but descending order defeats the natural sequence users build when creating milestones in phase/sprint order.

Root cause

In src/web/components/MilestonesPage.tsx, the sortByIdDesc comparator returns bNum - aNum, sorting largest ID first:

// Sort milestones by ID descending (newest first - IDs are sequential m-0, m-1, etc.)
const sortByIdDesc = (a: MilestoneBucket, b: MilestoneBucket) => {
  ...
  return bNum - aNum;  // ← descending
};

Fix

Flip the comparator to ascending (aNum - bNum) so milestones display in creation order (m-1 → m-2 → m-3 …). Also renamed the function to sortByIdAsc and updated comments for clarity.

The fallback value for non-m-N milestones was also changed from -1 to Number.MAX_SAFE_INTEGER so that milestones without a numeric ID sort to the end rather than colliding at the front.

Behavior change

Before	After
m-6 (Phase 9) first	m-3 (Phase 6) first
m-5 (Phase 8) second	m-4 (Phase 7) second
m-4 (Phase 7) third	m-5 (Phase 8) third
m-3 (Phase 6) last	m-6 (Phase 9) last

This matches what users expect when they name milestones in phase/sprint sequence.

Testing

The change is a single-line logic inversion in the comparator function. No new test assertions exist for this display order in the existing test suite (web-milestones-page-search.test.tsx, web-milestones-page-unassigned-filter.test.tsx).