M7: Every-line Composer for ragged text

Illustrator's Every-line Composer balances the breaks of the whole
paragraph for left/centre/right aligned text too, not only justified
text. VectorCraft only composed justified area text; ragged text was
always broken greedily.

- Model: ParaStyle.composer (vectorcraft_doc::Composer, re-exported by
  vectorcraft-text), Every-line by default like Illustrator, saved only
  when Single-line. layout() reads it from the object;
  LayoutOptions.composer is now an Option override for tests.
- Composer: the justified gate is gone. Ragged lines never shrink (a
  line that doesn't fit ends the node), badness is 100*r^3 with r = the
  line's leftover space over a rag zone of 1/6 of the width (finite for
  lines without spaces); the last line is free unless shorter than 1/3
  of the width (measured in zones of 1/3), so a lone short word on the
  last line pulls a word down. Hyphens cost 25 in ragged text (50 in
  justified). Knuth-Plass fitness classes with adjacency demerits
  (justified 10000, ragged 1000). Lines past the last width change
  share one node key, active nodes are capped (4096) and paragraphs
  over 200k glyphs break single-line, so work stays bounded; ragged
  tries a tolerance of one rag zone, then any fitting breaks, then
  falls back to greedy.
- text.setFormat {composer: "singleLine"|"everyLine"}; the Paragraph
  panel menu's composer items work with a check mark (Reset Panel goes
  back to Every-line).
- Tests: ragged Every-line moves "or" down in "Destroy all creatures
  with toughness X or less." where greedy leaves "less." alone; the rag
  of long paragraphs is no worse than greedy (sum of squared leftover
  and of neighbour differences); Single-line is greedy; the 10k-char
  layout budget covers ragged text; command test with undo; native
  format round trip (rich_session's text is now Single-line).
  No existing test needed changing: the justified tests and
  hyphenated_layout_adds_hyphens (ragged, now Every-line) still pass.

Auto alignment (start of the paragraph direction) is ragged; a wrapped
line's Mojikumi flush opening bracket gives its half em back to the
composer, as in the line loop; tests cover Auto in both directions.

Layout of 10k chars, release: justified Every-line 5.6 ms, ragged
Every-line 5.8 ms, ragged Single-line 4.8 ms.

docs/mcp.md

@@ -2549,6 +2549,20 @@ canvas as they export. `object.blend.expand` and `object.blend.release` keep the
 opacity mask and appearance (Release on a group around the keys and spine when the blend has any), and
 `object.expand` with `object: true` expands the blends in the selection.
 
+## Paragraph composer
+
+`text.setFormat {ids?, composer: "singleLine"|"everyLine"}` sets how a text object's lines are broken (the Paragraph
+panel menu's Single-line and Every-line Composer; stored in the paragraph attributes as `para.composer`, saved only
+when it is Single-line). Every-line, the default, picks the breaks of the whole paragraph together in area type:
+justified text gets even word spacing, ragged text (left, centre or right aligned) an even rag, so it may move a word
+that fits to the next line to avoid a lone short word on the last line or a full line next to a short one.
+Single-line fills each line as far as it goes. Point type and type on a path have no line width, so both composers
+give the same result there; paragraphs that mix type sizes fall back to Single-line.
+
+```json
+{"name":"run_command","arguments":{"command":"text.setFormat","params":{"ids":[7],"composer":"singleLine"}}}
+```
+
 ## Editing envelopes
 
 `object.envelope.editContents {editing}` switches between editing the envelope and its contents (the menu item reads