docs: specify the Spam view, the spam move and Empty Spam

Items 187, 190 and 195, settled with the user and specified together in
docs/superpowers/specs/2026-09-10-spam-view-design.md. Nothing is built
yet; implementation follows on a branch.

Mark spam becomes a move into the account's spam folder, following item
103's Delete-to-trash design rather than inventing a second mechanism: a
mandatory per-account `spam` key, a path-based threaded Spam filter, and
a repeatable cleanup pass for the mail the tag-only action stranded.
`unread` is stripped by the move (item 195, verified in the code: the
call names `spam` and `inbox` and nothing else). The message-bar button
carries `bug` with `mail-mark-junk` as its fallback, measured against the
user's icon theme, where the standard name draws a warning octagon and
`bug` draws the beetle the notes asked for; a bare `bug` was rejected
because it resolves in 0 of the 24 system themes and would leave a blank
button.

Two changes came from the user after the first draft and both improved
it. The origin tag is renamed `deleted-from:` -> `moved-from:`, which the
first pass had rejected on a migration cost that turned out to be 8
messages carrying one distinct value; and Empty Spam moves mail to the
trash per account, which needs no new grouping because trashMessages()
already resolves each message's own account.

A message can therefore leave two folders in turn, and the existing
reader takes the first matching tag and breaks. Rather than encode
ordering in the tag, which notmuch's unordered tag set cannot answer, a
move overwrites the origin instead of appending: one tag ever, one hop
back per Restore.

Empty Spam inherits neither of empty_trash's safeguards, deliberately. It
moves rather than destroys, so it has an inverse, and a confirmation on
an undoable action is the defect AGENTS.md names.

Item 197 is filed for a future "not spam": Restore already covers what
this application moved, and reverting the provider's own filter needs a
destination rule and possibly a sidecar, neither of which is decided.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LrqM5LJGAQEryvs5r7usM1

0 files changed, 0 insertions, 0 deletions