Close F7, F5 and F8 before resuming burn-in

F7, security. An unset surface token makes the middleware skip its check, so a
full-control surface with no credential is an open control plane rather than a
closed one. With ORCHESTRA_TUI_TOKEN unset, any LAN caller could lease, release,
complete or block any task by declaring one header, which is how this session's
manual leases were issued. authz.RequireCredentials now refuses startup instead
of logging. Web is exempt: Sessions makes its login mandatory.

F5, lifecycle. router.go's silent `continue` was the first bug, not the
predicate behind it. Every eligibility gate now records a router.Rejection with
task, herdr and reason, exposed at GET /v1/router/health, reset per pass. No
gate was weakened: a direct Store.Lease succeeding proves the lease path, not
that eligibility should have selected that worker.

F8, correctness. Reconcile iterated every configured source for every task, so a
task's external id was looked up in whatever repository each source pointed at.
Once two repositories share an issue number, an unrelated human comment becomes
an authoritative decision for the wrong task. Reconciliation is now bound to
task.Source, the provider:project identity the ingest stamped, and a source that
cannot prove it owns the task is skipped. A task with no matching source
reconciles to nothing and still launches, because nothing to import is not a
failure to read.

The integration fixture ingested from "jsonl" while reconciling from "gitea",
which is exactly the shape F8 makes impossible; it now ingests from the source
it reconciles.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

internal/router/router_test.go

@@ -2,6 +2,9 @@ package router
 
 import (
 	"encoding/json"
+	"errors"
+	"strings"
+
 	"orchestra/internal/authz"
 	"orchestra/internal/domain"
 	"orchestra/internal/registry"
@@ -299,3 +302,74 @@ func TestQuotaWindowsAreIndependent(t *testing.T) {
 		t.Fatal("bounded harness without a native usage receipt must fail closed")
 	}
 }
+
+// Every eligibility gate must say why. A silent `continue` is
+// indistinguishable from an empty queue: during burn-in a task sat queued
+// while every gate checked out by hand, and the router reported nothing.
+func TestAssignPendingRecordsWhyItPlacedNothing(t *testing.T) {
+	s, err := store.Open(t.TempDir())
+	if err != nil {
+		t.Fatal(err)
+	}
+	r, err := registry.New(registry.Config{
+		Projects: []registry.Project{{ID: "p", MachineAffinity: []string{"m"}}},
+		Machines: []registry.Machine{{ID: "m", Address: "unused"}},
+		Herdrs:   []registry.Herdr{{ID: "h", MachineID: "m", Concurrency: 1}},
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	b, _ := json.Marshal(map[string]any{"source": "test", "external_id": "why", "project": "p"})
+	if err := s.Append(domain.Event{ID: "create", TaskID: "t", Type: "TaskCreated", Version: 1, Payload: b, Surface: string(authz.System)}); err != nil {
+		t.Fatal(err)
+	}
+
+	// The live shape that went undiagnosed: a worker that has not declared the
+	// project. Everything else about it looks healthy.
+	rt := Router{Store: s, Registry: r, Reachability: reachable{}, Availability: projectAvailability{projects: map[string]bool{}}}
+	if got, err := rt.AssignPending(); err != nil || len(got) != 0 {
+		t.Fatalf("lease = %#v, %v", got, err)
+	}
+	reasons := rt.Rejections()
+	if len(reasons) == 0 {
+		t.Fatal("the router placed nothing and said nothing")
+	}
+	var named bool
+	for _, rej := range reasons {
+		if rej.TaskID != "t" {
+			t.Fatalf("rejection for the wrong task: %+v", rej)
+		}
+		if rej.HerdrID == "h" && strings.Contains(rej.Reason, "has not declared project") {
+			named = true
+		}
+	}
+	if !named {
+		t.Fatalf("no rejection names the failing gate: %+v", reasons)
+	}
+
+	// A pre-lease refusal is the gate that fails closed on purpose, and it must
+	// also be visible rather than looking like "no candidates".
+	rt.Availability = projectAvailability{projects: map[string]bool{"h/p": true}}
+	s.PreLease = func(string) error { return errors.New("gitea unreachable") }
+	if got, err := rt.AssignPending(); err != nil || len(got) != 0 {
+		t.Fatalf("lease despite pre-lease refusal = %#v, %v", got, err)
+	}
+	found := false
+	for _, rej := range rt.Rejections() {
+		if strings.Contains(rej.Reason, "lease refused") && strings.Contains(rej.Reason, "gitea unreachable") {
+			found = true
+		}
+	}
+	if !found {
+		t.Fatalf("pre-lease refusal not reported: %+v", rt.Rejections())
+	}
+
+	// A successful pass leaves nothing behind to misread.
+	s.PreLease = nil
+	if got, err := rt.AssignPending(); err != nil || len(got) != 1 {
+		t.Fatalf("lease = %#v, %v", got, err)
+	}
+	if reasons := rt.Rejections(); len(reasons) != 0 {
+		t.Fatalf("stale rejections after a successful pass: %+v", reasons)
+	}
+}