Merge remote-tracking branch 'origin/main' into quaver

# Conflicts:
#	web/src/structured.ts

docs/STRUCTURED-VIEW.md

@@ -35,6 +35,22 @@ session's worktree holds unsaved work — applies to a structured session
 exactly as it does to a terminal one; only what gets terminated differs (an
 ACP handle instead of a tmux pane).
 
+## Choosing the view
+
+`view` is fixed at spawn and never changes. Every client picks it the same
+way, from the resolved command alone
+(`maestro_protocol::display::supports_structured_view`): a command that
+resolves to Claude Code or Codex spawns **Structured** by default, anything
+else spawns **Terminal**. The operator can override the default — the web and
+TUI spawn forms show the checkbox ticked and let it be unticked, and
+`maestro spawn` takes `--terminal` (or `--structured`, which sends the request
+even for a command the CLI does not recognise and lets the daemon refuse it).
+Once the operator works the toggle, a later command change never re-ticks it
+under them; it can still be forced off when the new command has no adapter.
+
+The daemon is the last word: a `Structured` request for a command with no
+adapter is refused there, whichever client sent it.
+
 ## The adapter
 
 The resolved structured command selects a provider adapter. Its binary is
@@ -302,6 +318,26 @@ pending decision, entirely on the daemon side:
 
 ## Prompt and cancel: bounded liveness
 
+The web composer accepts up to ten files through its attachment picker, file
+drop, or clipboard. Pasted text of at least 4,000 characters or 40 lines becomes
+a UTF-8 `.txt` attachment. Shorter pastes stay in the composer. Attachments can
+be removed before sending; failed sends retain the draft and attachments.
+Pastes also stay inline when all ten attachment slots are occupied or the text
+exceeds the 20 MiB file limit.
+
+On send, `POST /api/sessions/:id/structured/attachments?name=<filename>` uploads
+each file as raw bytes (20 MiB maximum) and returns its absolute `path`.
+Only live structured sessions accept uploads. Filenames are limited to 180
+bytes and cannot contain directory separators or control characters. Files get unique names and private
+file permissions in `<id>.attachments` beside the session sidecar. They persist
+across daemon restarts; removing a composer chip does not delete uploaded data.
+There is currently no automatic attachment cleanup.
+
+The prompt includes each filename and host path so the adapter can read it
+through its own file tools, including images when the provider supports them.
+These references are persisted in the ordinary user transcript row. Attachment
+bytes are not embedded in ACP messages or transcript history.
+
 `POST /api/sessions/:id/structured/prompt` and `.../cancel` are serialized
 against each other through one per-session `operation` lock
 (`AcpEventStream::operation`), because ACP permission callbacks carry no