feat(routing): wire the wrap-up cross-project router end to end

This closes the build half of the wrap-up routing spec: Phases 2 and 4 here, with the engine and discovery already shipped.

inbox.org's "File as TODO" disposition now runs route_recommend on each keeper and stamps :ROUTE_CANDIDATE: <destination> on strong and weak matches, so the wrap-up router has a candidate set without ever scanning the standing backlog. wrap-it-up.org Step 3 gains the optional router after the inbox sanity check, with the gate-vs-optional split named in the prose: surface the batch with destinations and confidence labels, then go or skip. An empty set stays silent.

The go path is mechanical rather than prose-driven: the new route-batch helper lists candidates read-only, and on go extracts each subtree (children ride along, markers stripped, headings promoted), delivers it via inbox-send for provenance, and removes the local copy only after a successful send, rewriting todo.org per send so a crash never strands an already-sent task locally. Overlapping candidate spans (a tagged child inside a tagged parent) are a loud conflict, left in place with a non-zero exit, because routing either span would silently take the other along.

A 13-test bats suite covers list/backlog exclusion, empty-set silence, delivery with provenance and children, promotion, drawer pruning, the no-todo.org destination, failed-send recovery with the marker intact, the nested-candidate conflict, and duplicate-marker dedupe. cross-project.md notes the router as a sanctioned cross-project write path.

1 files changed, 2 insertions, 0 deletions

diff --git a/claude-rules/cross-project.md b/claude-rules/cross-project.md
index caceec9..73c0e1b 100644
--- a/claude-rules/cross-project.md
+++ b/claude-rules/cross-project.md
@@ -35,6 +35,8 @@ Two acceptable outcomes:
    ```
 
    Output filenames follow `YYYY-MM-DD-HHMM-from-<this-project>-<slug>.<ext>` automatically, so the target's next session sees the source + timestamp at a glance without you having to construct the name. Fall back to `Write`/`Edit` only when the script isn't available (e.g. a freshly-cloned project before the first startup-rsync).
+
+   The wrap-up cross-project router rides this same sanctioned path: at wrap time, `wrap-it-up.org`'s router step delivers `:ROUTE_CANDIDATE:`-tagged keeper tasks to their home projects' inboxes via `route-batch` → `inbox-send` (never a direct foreign `todo.org` write), and the destination's own inbox processing files each task per its conventions.
 2. **"Switch projects"** — stop. Let the user reopen the agent session in the right cwd.
 
 Don't assume which one was meant. Either guess is wrong half the time and the cost of asking once is one short turn.