fix(pipeline,api,wing): never archive a note as processed when nothing was ingested; titles do not merge sources; ties prefer the page on disk (review of #211, pass 3)

- in a wing, an ingest that writes no source page is an error: the note goes to
  raw/failed with the warnings in log.md instead of leaving the inbox as
  'processed' (model returned [], only invalid types, only clashing entities)
- the wing's source path is deterministic, so Resolve no longer redirects a
  source onto another note's page because the model gave both the same title
  ('Home'); that overwrote the hash and the text
- a batch tie between concept and entity prefers the page already on disk, so
  its update is not lost; the wing's own source page keeps its slug even when a
  foreign page shares it
- brain_pending lists an unreadable (over-cap) note with the reason instead of
  dropping it; the client filter's 4 KiB match-span limit is documented
Each has a test that fails without it (mutation-checked).

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

ingestion/internal/api/promote.go

@@ -97,6 +97,16 @@ func listNotes(root *os.Root, queue string) ([]PendingNote, error) {
 		}
 		raw, info, readErr := readRawNote(root, e.Name())
 		if readErr != nil {
+			// Not skipped: a note that cannot be read (over the cap, say) must
+			// not silently vanish from the queue it is waiting in.
+			fi, ierr := root.Lstat(e.Name())
+			if ierr != nil {
+				continue
+			}
+			out = append(out, PendingNote{
+				Filename: e.Name(), CreatedAt: fi.ModTime().UTC().Format(time.RFC3339), SizeBytes: fi.Size(),
+				Excerpt: "(cannot be read: " + readErr.Error() + ")", Queue: queue,
+			})
 			continue
 		}
 		fm, body := parseFrontmatter(string(raw))

ingestion/internal/api/promote_queue_test.go

@@ -190,3 +190,21 @@ func TestReadCapped_StopsAtTheCap(t *testing.T) {
 	assert.Contains(t, err.Error(), "exceeds")
 	assert.LessOrEqual(t, e.n, int64(1000+1+32*1024), "pulled far more than the cap: %d", e.n)
 }
+
+// An .md over the read cap used to vanish from the listing (readRawNote failed
+// and the entry was skipped). It must stay visible, with the reason.
+func TestListPending_AnUnreadableNoteIsListedWithTheReason(t *testing.T) {
+	dir := t.TempDir()
+	require.NoError(t, os.MkdirAll(filepath.Join(dir, "raw"), 0o755))
+	require.NoError(t, os.WriteFile(filepath.Join(dir, "raw", "huge.md"), []byte(strings.Repeat("x", 200)), 0o644))
+	prev := maxRawNoteBytes
+	maxRawNoteBytes = 100
+	t.Cleanup(func() { maxRawNoteBytes = prev })
+
+	got, err := ListPending(dir)
+	require.NoError(t, err)
+	require.Len(t, got, 1)
+	assert.Equal(t, "huge.md", got[0].Filename)
+	assert.Contains(t, got[0].Excerpt, "cannot be read")
+	assert.Contains(t, got[0].Excerpt, "exceeds")
+}