fix(runtime): report only live structured sessions in worktree ps

The status feed's `published` map is a broadcast cache, not a roster. It
deliberately never retracts — an evicted idle session is still idle, and a
reloading renderer must not lose every settled row — so enumerating it lists
every session the host has ever opened, and eviction's `forget-session` step
deletes the session from the live map while touching nothing else.

Reading it as a roster made `worktree ps` report a closed chat forever. The
sharp edge is a chat closed while an approval was pending: a deliberate close
does not settle a pending prompt, so the retained summary stays `attention`,
maps to a `blocked` row, and merges the worktree to `permission` for the whole
30-minute freshness window — on the CLI and on the mobile sidebar it backs.

The poller now answers from the sessions the host still holds, intersecting the
live map with the retained projections. `subscribe()` and its snapshot are
untouched: retention there is the point. Gating on the live session set rather
than the visible tabs keeps a headless orchestration worker listed, which is
what the agent-facing surface is for.

Also folds out two things the enumerator left behind: the working/attention/idle
to working/blocked/done mapping now lives once in the shared projection module
instead of once per process, which is what actually enforces "the CLI and the
GUI cannot disagree"; and the structured row source no longer builds a
write-only `payload` behind an `as` cast that compensated for nothing. The
structured source construction moves to its own module to keep
runtime-worktree-agent-rows.ts clear of the 300-line cap.

src/main/runtime/runtime-worktree-agent-rows-structured.test.ts

@@ -93,13 +93,13 @@ describe('terminal listing is deliberately left alone', () => {
     )
     // Guard the guard: an empty read would make every assertion below vacuously true.
     expect(listing).toContain('async listTerminals(')
-    expect(listing).not.toContain('publishedStatusSummaries')
+    expect(listing).not.toContain('liveSessionStatusSummaries')
     expect(listing).not.toContain('structuredSummaries')
 
     const worktreePs = await readFile(
       new URL('./orca-runtime-get-worktree-ps.ts', import.meta.url),
       'utf8'
     )
-    expect(worktreePs).toContain('publishedStatusSummaries')
+    expect(worktreePs).toContain('liveSessionStatusSummaries')
   })
 })