SymbolInfo restructure: one structured Documentation accessor, no raw docblock string

[Firehed]

SymbolInfoInterface carries structured documentation. The raw docblock string field is removed.

Blocked by #541 (docblock parser utility) and #538 (one symbol interface).

Unblocks #520 (DocblockTypeSource reads the parsed docblock off SymbolInfoInterface).

Motivation

Today ClassInfo, MethodInfo, PropertyInfo, ConstantInfo, and EnumCaseInfo each carry a ?string $docblock field. getDocumentation() returns text derived from it by DocblockParser::extractDescription. Any docblock-typing work would naturally reach for the same string, at which point "what does the docblock say for this symbol" has two consumers of the raw text, and the source-specific parsing rules leak into every caller.

If SymbolInfoInterface carries a structured Documentation populated once at construction time, the raw string never crosses the interface and consumers ask for the fact they want by name.

Shape

• One accessor on SymbolInfoInterface: getDocumentation(): Documentation. No separate parsed-docblock accessor.
• Documentation is one value type carrying the description, the deprecation flag and message, and the parsed docblock subtree from Adopt external docblock parser behind ParsedDocblock utility #541. Everyone reads from it.
• Each SymbolInfoInterface producer reads the docblock text in the way natural to its source and calls DocblockParser::parse(text, NameContext). A reflected symbol's NameContext carries its declaring namespace only, no import table; record that where the producer builds it.
• The raw string field is removed from every implementation.
• HasSymbolLocationTrait's DocblockParser::extractDescription call goes; ResolvedSymbolPresenter reads the structured value.
• ExpressionResolver's @var element-type inference reads the parsed docblock through Documentation.

Rule edits this needs

The disallowedMethodCalls entry for DocblockParser::extractDescription is removed with the method. Any allowlist path or ledger row that named DocblockParser, HasSymbolLocationTrait, or ResolvedSymbolPresenter as a docblock-string reader is updated. The human makes these edits.

Done

• No $docblock string field on any Domain\*Info class.
• SymbolInfoInterface::getDocumentation() returns Documentation.
• Every producer populates it at construction.
• No caller reads a raw docblock string outside Domain\Docblock\DocblockParser.
• Hover, completion detail, and signature help output is byte-for-byte unchanged (parity goldens green).
• composer test green.

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Issue body drafted by AI.

[Firehed]

Closing AI-authored issues that cannot be completed as written