Stabilize list contexts after dropped wrappers

[jmanico]

Summary

• keep an inferred list that produced no wrapper from capturing later text or a following select
• keep browser-ignored inferred items logical-only inside an emitted select, close output-option siblings across a dropped nested select, and close a free output item before a dropped list infers its sibling
• add hostile round-trip regressions for the li-only, li/option, and li/select policy residuals from Never emit the list item implied for content a select cannot hold #494
• cover the four Give a caption or column group under a dropped template its table in Sanitizers.TABLES #499 policy/input residuals (eight non-idempotence/tree-mutation flags) with their reduced dropped-template cases; they share the same outputless-list seam
• preserve the logical nested-list context when the output policy is still inside an emitted li, fixing the reduced <li><ol><tbody></li>&amp; browser-tree mutation found after updating from Stabilize text after bare parts of a dropped table #501

Verification

• merged current main after Stabilize text after bare parts of a dropped table #501 (0932b99)
• full sanitizer probe (678,920 rows), compared row-by-row against Stabilize text after bare parts of a dropped table #501 with the identical probe source, binary, corpus, and seeds: zero gained flags of any kind; all 83 historical Never emit the list item implied for content a select cannot hold #494 rows remain clear
• full event/limit probe (36,063 rows), compared the same way: zero gained flags of any kind; all four Give a caption or column group under a dropped template its table in Sanitizers.TABLES #499 target rows and their eight flags remain clear
• JAVA_HOME=/opt/homebrew/opt/openjdk@21/libexec/openjdk.jdk/Contents/Home ./mvnw -o -ntp -B clean verify (691 library tests and 7 example tests pass)

Follow-up to #494, #499, and #492.