refactor: ValueCleaner is the named choke point (H1)

The choke point moves out of AttrWriter into ValueCleaner (catalog, the
composition's VariableRef, sanitizer): clean() (was AttrWriter::cleanValue),
kindOf(), guardPath() and the private cleanNode/kind/unknownKind/tightens with
VALUE_KEY, URL_KEY, URL_SEGMENT, STRICTNESS, BUILDER_ONLY (its docblock now sits
on it; STRUCTURE stays in AttrWriter). Code of the pipeline moved unchanged.
- ValueCleaner's docblock is the one canonical description: steps 0-8 with their
  rulings in code order, invariants I1-I3; the step comments in cleanNode carry
  the same numbers. AttrWriter/ShortformWriter/Composer/TextReplacer docblocks
  point there and keep only their own rules.
- ValueCleaner::textReplacementFor($module) holds the D10 rule that was a
  closure in DiviReplaceTextAbility::replace (text/html only, clean() by kind).
- AttrWriter, ShortformWriter and Composer take the ValueCleaner; DiviComposition
  builds one per composition (cleaner()).
Tests: the eight AttrWriterTest methods that only exercised cleanValue/kindOf
moved verbatim to ValueCleanerTest (clean/kindOf, ComposeFixture::cleaner());
mixed tests call the cleaner in place; +1 test for textReplacementFor. Every
provider row and per-test assertion count unchanged.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01At3V6SjwbMe6eMzVGW3Hs7

src/Integrations/Divi/Compose/TextReplacer.php

@@ -18,8 +18,8 @@ use LIT\MCP\Integrations\Divi\BlockTree\Serializer;
  * Rulings S8/S45: each string is tokenized (quote-aware tags, comments, entities, references,
  * raw-text bodies such as <script>); only text tokens are searched. A string with an
  * unterminated tag, quote, comment or reference and a hit is refused. The inserted text is the
- * replacement as the $clean callback returns it for that place (AttrWriter::cleanValue() in the
- * ability: sanitized by the field kind, markers rejected – rulings S2/S28). A string with no
+ * replacement as the $clean callback returns it for that place (ValueCleaner::textReplacementFor()
+ * in the ability: sanitized by the field kind, markers rejected – rulings S2/S28). A string with no
  * effective hit is returned as it is and never cleaned (Task 1 forward risk). A changed string
  * must keep every non-text token of the original byte for byte, gain only the inserted text's
  * own, add no reference marker, and an independent scan (HtmlContext) must see each replaced