"Reply with selection" no longer appends the selected text straight into
the composer. It now adds a named chip ("Context N") to a row above the
message box (composerSelectionChips). Chips can be renamed (double-click,
esc()-escaped) or removed (x); multiple stack. On send(),
_flushSelectionBlocksToComposer() materializes pending blocks into the
composer as **Name:** + markdown-quoted text, then the normal send path
runs unchanged on composer.value.
Regression-safety:
- _flushSelectionBlocksToComposer early-returns when no blocks are pending,
so send() is byte-identical for anyone who never uses the feature.
- loadSession() AND newSession() both clear pending blocks before replacing
S.session, so chips never leak across a sidebar switch OR a New Chat
(the New Chat clear + its regression test were added per Codex review).
- chip name/text rendered via esc(); XSS-safe.
Verified live (headless CDP drive): add/render/remove/rename, flush
produces correct markdown, empty-flush no-op, session-switch clears,
injected <img onerror=...> chip-name escaped (not executed).
Co-authored-by: Rod Boev <rod.boev@gmail.com>
