fix(text-wrapper): prevent boundary word duplication in line wrapping

[Cadons]

Three regressions found and fixed while re-validating this branch against main (b386ee8).

fix(text-wrapper) — duplicated boundary word when wrapping multi-word text

DocraftLoomTextWrapper::wrap_paragraph built the wrap candidate with
current_line.append(" ").append(word). std::string::append mutates the
object in place and returns a reference to itself, so this silently
overwrote current_line as a side effect of building candidate — not
just candidate. When the candidate didn't fit and the code fell back to
lines.push_back(current_line), current_line had already been
overwritten to include the overflowing word, so that word was pushed on
the current line and reprocessed onto the next one. Any <Text> (bare
or inside a table <Cell>) with 2+ words whose full width exceeded its
box duplicated the boundary word in the rendered PDF — a silent content
corruption, not just a layout glitch.

Fixed by building candidate without mutating current_line
(current_line + " " + word).

fix(loom-table) — table columns overflowing available width

resolve_table_column_widths gave every flexible column a share of the
full available_width even when another column in the same table had
an explicit width, instead of deducting that explicit width first. E.g.
with available_width = 200 and one column pinned to 150, the other
(flexible, weight 1) column used to get 200/2 = 100 instead of the 50
actually left over — total 250 > 200, silently overflowing the
page/body margin.

Flexible columns now only divide what's left after explicit-width columns
are deducted, and only those flexible columns are rescaled to close any
gap left by natural-width floors.

fix(loom-rectangle) — text/content overflowing rectangle bounds

visit(DocraftLoomRectangle*) in the rendering processor painted children
with no clip at all, unlike the equivalent visit(DocraftLoomCanvas*). A
child whose computed size exceeded the rectangle's own frame (e.g. a
<Text> whose own explicit width overrides the width relayed by its
parent <Rectangle>) painted past the rectangle's border instead of
being contained by it.

Now clipped the same way Canvas already is.

Verification

All three verified end-to-end via docraft_tool + rendered PDF (visual
before/after comparison for the wrapping duplication and the rectangle
clip), plus new/updated regression tests:

• DocraftLoomTextWrapperTest.* (new — the wrapper had no dedicated unit
  tests before this)
• DocraftLoomTableTest.ExplicitWidthIsRespectedAndRemainderRedistributed
  (updated — it previously asserted the buggy dilution as expected
  behavior)
• DocraftLoomRectangleTest.RenderingClipsChildrenToRectangleBoundsBracketedBySaveRestore
  (new — Rectangle's rendering pass had no test coverage before this)

Full suite: 430/430 passing.

[sonarqubecloud]

Quality Gate passed

Issues
2 New issues
1 Accepted issue

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarQube Cloud