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.

2 files changed, 34 insertions, 0 deletions

diff --git a/.ai/workflows/inbox.org b/.ai/workflows/inbox.org
index 5fc855f..ea45ae3 100644
--- a/.ai/workflows/inbox.org
+++ b/.ai/workflows/inbox.org
@@ -114,6 +114,14 @@ The item extends a task already filed. Update the parent TODO's body with a date
 ** File as TODO
 Substantive but waits, or needs design/triage before implementation. Add the TODO under =* <Project> Open Work= with priority + tags per the priority-scheme check (core §6). Body summarizes the proposal and links the inbox content if it's been moved to =docs/design/=. Delete the inbox file (or move it to =docs/design/= first if the content survives).
 
+*Route-candidate marking (feeds the wrap-up router).* After filing, check whether the keeper's inferred home is a different project:
+
+#+begin_src bash
+python3 .ai/scripts/route_recommend.py --item "<the keeper's heading + body text>" --exclude "$(basename "$PWD")"
+#+end_src
+
+On a =<destination>\tstrong= or =<destination>\tweak= result, stamp the new TODO's property drawer with =:ROUTE_CANDIDATE: <destination>= (create the drawer if the task has none). A =none= result stamps nothing, and a local keeper stays unstamped. The marker is the wrap-up router's entire candidate set — =wrap-it-up.org= Step 3 surfaces exactly the =:ROUTE_CANDIDATE:=-tagged tasks and offers to deliver each to its destination's inbox, never scanning the standing backlog. Stamping is cheap and reversible (the router's skip leaves the task in place; a wrong marker is one property line to delete), so prefer stamping on any plausible match — the human reviews the batch at wrap time.
+
 *Blocking-dependency handoff.* A special shape: another project sends a note that *this* project's work is blocking one of theirs ("your task X is blocked on us — we need Y"). File or link the owning task, tag it =:blocker:=, and name the requesting project in the body (see the cross-project dependency convention in =todo-format.md=). The =:blocker:= tag makes =open-tasks.org= surface that task *first*, since clearing it unblocks the other project. Dedup against an existing task rather than filing a duplicate. When the work later lands, drop =:blocker:= and notify the waiting project (=inbox-send <their-project> --text "Delivered: <what> — you're unblocked."=) so it can lift its own =:blocked:=.
 
 ** Defer
diff --git a/.ai/workflows/wrap-it-up.org b/.ai/workflows/wrap-it-up.org
index 4fa5a3a..d0c4e75 100644
--- a/.ai/workflows/wrap-it-up.org
+++ b/.ai/workflows/wrap-it-up.org
@@ -260,6 +260,32 @@ The check exempts =lint-followups.org= explicitly because lint-org runs earlier
 
 This integrates with =inbox.org= process mode, which stamps =:LAST_INBOX_PROCESS:= in =notes.org='s *Workflow State* section on completion. Wrap-up doesn't double-stamp. It only ensures the inbox carries nothing but the expected pipeline artifacts at session end.
 
+*** Cross-project router (optional — route filed keepers to their home projects)
+
+Runs directly after the inbox sanity check. The split between the two: the sanity check *gates* the wrap (a dirty inbox blocks until resolved); the router is *optional* (skipping it never blocks anything — the candidates just stay local until a future wrap). Spec: =docs/specs/wrapup-routing-spec.org= (D7/D8/D9).
+
+The candidate set is exactly the local tasks carrying a =:ROUTE_CANDIDATE:= property — keepers that inbox process mode filed this session whose inferred home is another project. Never scan the standing backlog.
+
+#+begin_src bash
+.ai/scripts/route-batch --list
+#+end_src
+
+*Empty set = zero interaction.* =--list= prints nothing when there are no candidates; continue the wrap silently — no prompt, no "0 items" line.
+
+When candidates exist, surface the batch as one line per task — the task heading, the destination project, the delivery mode (=inbox-send= file handoff), and the engine's confidence — then offer exactly two options: *go* (route the whole batch) or *skip* (leave everything local). Derive each confidence label by running the engine on the task's heading + body (=python3 .ai/scripts/route_recommend.py --item "..." --exclude "$(basename "$PWD")"=); label weak matches visibly ("weak — verify the destination") so a low-confidence route gets a human glance before the keystroke.
+
+On *go*:
+
+#+begin_src bash
+.ai/scripts/route-batch --go
+#+end_src
+
+Per candidate, the helper writes the task's subtree (children ride along; =:ROUTE_CANDIDATE:= stripped, headings promoted to top level) to a one-task handoff, delivers it via =inbox-send <destination> --file= (so the =from-<this-project>= provenance is stamped and the destination's inbox process mode dispositions it as a single item), and only after a successful send removes the subtree from the local =todo.org= — a single-file local edit the wrap is already committing. A failed send leaves that task in place and exits non-zero; report it and continue the wrap. Never write the destination's =todo.org= directly; its own inbox processing files the task per its conventions.
+
+On *skip*, leave every candidate in place, marker included — they resurface next wrap.
+
+Mis-routes are recoverable: the receiving project rejects via inbox process mode's reject-from-another-project flow, which returns the item to this project's inbox with the rationale. That reject path is why removing the local source on send is safe.
+
 *** Review-habit health check (surface a slipped daily task-review)
 
 The daily task-review habit walks the open top-level tasks on a rotating cycle, stamping =:LAST_REVIEWED:= as it goes (see =task-review.org=). This check is the watchdog for that habit. When tasks have gone too long unreviewed, the habit has slipped, and the wrap-up says so in one line — it does not re-list the tasks.