Lint: Register Phase-2 blockers in UnsupportedRegistry (ternary, .=, break)

[PurHur]

Problem

phpc lint maps some unsupported CFG kinds to GitHub issues via lib/Lint/UnsupportedRegistry.php, but several Phase-2 P0 constructs still fall through to generic errors:

Syntax	Tracking issue	Registry today
Ternary ?:	#114	missing (mis-filed Expr_Yield → #114)
Compound .= / +=	#136	missing
break / continue	#115	missing
match	#143	missing

Contributors running ./phpc lint examples/003-MiniWebApp/... do not get actionable issue links for common blockers.

Goal

Extend UnsupportedRegistry::KIND_TO_ISSUE and docs/unsupported-syntax.md so lint output references the correct issue numbers.

Tasks

• Audit lib/Compiler.php LogicException paths for stmt/expr types
• Add mappings for ternary CFG ops, compound assign, break/continue, match
• Fix incorrect mappings (Expr_Yield → Language: Generators (yield and yield from) #167, not Language: Ternary operator (?:) in compiler pipeline #114)
• Unit test: UnsupportedRegistry::trackingIssueForKind() for each added kind
• Regenerate or update docs/unsupported-syntax.md if generated from registry

Acceptance criteria

./phpc lint -r '\$x = \$a ? \$b : \$c;'

stderr mentions #114 (or structured lint code linking to it).

Verification (local only)

./script/ci-local.sh --filter UnsupportedRegistry
# or Docker:
docker run --rm -v "$(pwd):/compiler" -w /compiler php-compiler:22.04-dev \
  vendor/bin/phpunit --filter Lint

Dependencies

• DevEx: phpc lint reports unsupported Stmt/Expr before LogicException #236 structured lint (closed) — builds on same pipeline

Blocks

• Reference: MiniWebApp lint-first skeleton (examples/003-MiniWebApp) #246 MiniWebApp skeleton lint-first workflow