fix(ohos): keep inline-box chrome with text

[bytemain]

Problem

The task Tencent-TDS#942 OHOS screenshot contains no literal [ / ] around the mention or task ref. The narrow yellow fragment left at the preceding line end is the inline box's own leading edge/chrome placeholder, while @artin / #188 starts on the next line.

OHOS currently lowers a text-only inline-box group as:

leading OH_Drawing placeholder → U+2060 → child text → U+2060 → trailing placeholder

That cannot be atomic. OpenHarmony OH_Drawing_TypographyHandlerAddPlaceholder reaches SkParagraph addPlaceholder(), which inserts U+FFFC. In OpenHarmony Skia TextWrapper, placeholders explicitly end the current word and become their own word, before normal U+2060 behavior can bind the units.

Change

For inline-box groups whose children are ordinary text:

U+200B  U+2011  U+2060 child U+2060  U+2011  U+200B
break   edge                         edge    break

• Each U+2011 NON-BREAKING HYPHEN is rendered at font size 0, so its glyph advance is zero; letterSpacing supplies the exact reserved edge width (margin + border + padding).
• U+2011 has Unicode line-break class GL and is not whitespace, so the edge stays in the token's non-breaking word and cannot become SkParagraph's intra-word-space fallback.
• U+200B stays outside the click/chrome range, preserving a legal break before and after the complete group.
• The existing U+2060 joins text children within the group.
• Groups containing placeholder-backed children keep the existing placeholder lowering unchanged.
• Layout-only edge/boundary clusters continue mapping to zero semantic characters. Crossing the trailing edge maps to the original semantic token exactly once, preserving selection/copy/accessibility source text.
• Chrome/click ranges include the exact reserved edges; ordinary CJK/URL text outside the group is untouched.

U+2060 itself is deliberately not used as the width carrier: OpenHarmony API 26+ disables letter spacing for control characters, and ICU classifies U+2060 (Cf) as control.

Evidence

Source chain inspected at the platform commits used by OHOS:

• openharmony/graphic_graphic_2d@fb7c3ba...
  • drawing_text_typography.cpp
  • typography_create.cpp
  • paragraph_builder_impl.cpp
• openharmony/third_party_skia@fd56c1f8...
  • ParagraphBuilderImpl.cpp
  • TextWrapper.cpp
  • ParagraphImpl.cpp
  • Run.cpp
  • OneLineShaper.cpp
• Skia's pinned HarfBuzz exact is a070f9eb...; font size 0 and the non-control GL carrier avoid default-ignorable/control-spacing ambiguity.

Validation

• core-render-ohos/src/test/cpp/run_inline_box_atomic_text_edge_test.sh — PASS (-Wall -Wextra -Werror), with a bracket-free near-line-end @artin regression shape.
• Existing OHOS scroller source contract — PASS.
• OHOS arm64 KRRichTextShadow.cpp SDK syntax compile — PASS.
• git diff --check — PASS.
• Hosted exact matrix, including fresh OHOS arm64 production compile/link — pending on this Draft PR.

The prior bracket-keyed PR #104 is closed and VOID. It must not be reopened, merged, or consumed.

Task: Mobile task Tencent-TDS#942