Step 2: Feature Description — Board/Activity Carry-Back (+ Board Score column)

Problem

Board and Activity list rows show full-precision timestamps instead of the scannable relative format Users already has, and Board has no way to see or sort by a thread's score even though it's already computed and already drives default ordering.

User stories

• As a Board/Activity reader, I want list rows to show "2 days ago"-style relative dates (with the exact timestamp still available on hover) so that I can scan recency at a glance, consistent with Users.

• As a Board reader, I want a visible Score column so that I can see and sort by a thread's score instead of inferring it only from default ordering.

Core requirements

• Board's paned_board_thread_list.php and Activity's paned_activity_item_row.php / paned_activity_commit_row.php render dates via $relativeTimestamp, keeping the full-format tooltip.

• No other use of $timestamp in these views changes (e.g., any full-format date already shown elsewhere stays as-is).

• Board list gains a "Score" column, sortable via the existing header-button pattern, sourced from threads.score_total.

• New Score column follows the same head/row/sort-attribute conventions as Subject/From/Date/Replies — no bespoke sort logic.

• No database schema changes; no changes to score computation.

Shared component inventory

• $relativeTimestamp / $timestamp closures in src/ForumRewrite/View/TemplateRenderer.php — reused as-is (already canonical, added in Stage 19 for Users).

• Sortable-column mechanism in public/assets/paned_board_reader.js (data-paned-sort-column / data-paned-sort-<col>) — reused as-is, no JS changes expected since it's column-agnostic.

• threads.score_total (populated by ReadModelBuilder) — reused as-is, no new field.

Simple user flow

1. User opens Board or Activity.

2. List rows show relative dates instead of full timestamps; hovering a date reveals the exact time.

3. On Board, user sees a Score column and can click its header to sort ascending/descending, same as other columns.

Success criteria

• Board and Activity list rows display relative dates matching Users' format and tooltip behavior.

• Board list displays a Score column reflecting threads.score_total, sortable via its header button, with sort state reflected in the URL like other Board columns.

• No regressions to existing Board/Activity sort behavior, column layout, or full-format date displays elsewhere.