v0.6.0

--style system: a palette built from the colors your terminal is already
using. Nothing resolves differently than it did — the only change to auto,
the default, is that its documentation now describes it accurately.

Added

• --style system builds the whole palette out of the terminal's own
  colors rather than shipping one. The page and the text are taken verbatim
  from OSC 10 and OSC 11; cards, borders and the muted tone step off them;
  headings, links and the five callout hues come from the OSC 4 ANSI slots.
  Every color that ends up as text is held to a WCAG contrast floor against
  the page and walked toward the foreground until it clears — which is what
  keeps a light scheme's yellow from becoming an unreadable heading, and what
  makes this survive a colorscheme that reports every slot as black.

  It is listed by themes, selectable in the s picker, and saved to the
  configuration file like any other. Anything that will not answer falls back
  to a shipped palette rather than refusing to start: screen, which swallows
  the question, and tmux, which answers the device query and nothing else.
  Only a terminal that answers nothing at all pays the 100 ms timeout; where
  the device query comes back — tmux included — the fallback is immediate.

• terminal-query, in [general], and MARQUEE_TERMINAL_QUERY. Default
  on; off stops the terminal being asked anything, for a terminal that prints
  the question instead of answering it.

Changed

• --style auto is now documented as what it is: an alias for slate. It
  has carried a promise to follow the terminal's background since the
  beginning and has never kept it — the seam was there from the start and both
  callers passed "unknown", so it has always answered the dark palette. The
  behavior is untouched, deliberately: it was the default, and the first
  release to start keeping that promise would move every reader on a light
  terminal from slate to paper without being asked. The documentation now
  matches the code instead of the other way round, and --style system is
  where following the terminal lives.

• The default style is now slate rather than auto, which is the same
  theme by another name — mmd config says style = "slate" where it used to
  say style = "auto". Naming the palette states the default instead of
  deferring it to whatever auto happens to mean, so changing what a reader
  who never chose a theme sees now takes changing the default, deliberately,
  rather than falling out of a change to auto. auto remains a name
  --style and [general] style accept.

  Nothing resolves differently. -s auto is byte-for-byte -s slate, with a
  terminal sitting there answering or without one.

• The reader takes the mouse wheel by default, where it used to wait to be
  asked with -m. Not a preference: a terminal whose alternate scroll mode is
  on — which is the default in most of them — answers a wheel that nobody
  claimed by manufacturing arrow keys, multiplied by whatever scroll factor it
  was configured with. They arrive as ordinary keystrokes, indistinguishable
  from a hand on j, so a stray touchpad brush would yank the document away
  from someone reading it with the keyboard, and only while the pointer
  happened to be over the window. Claiming the wheel is what stops the terminal
  doing that, and it makes a tick the same three lines everywhere instead of a
  number the terminal picked.

  The cost is that selecting text with the mouse needs shift held while the
  reader is open, which is the trade less --mouse makes. --no-mouse and
  mouse = false hand the wheel back; -m is still accepted, still means the
  same thing, and still overrides a configuration file that turned it off.

• The wheel moves the pane the movement keys would move, rather than the
  document whatever has focus. Tab into the contents pane and the wheel moves
  the outline; open the key reference and it moves the reference; in the file
  browser it moves the list. It resolves to the same Action a key does, so
  the two cannot drift apart, and a pane that grows movement keys gets the
  wheel with them. A sideways tick still only pans a document — h and l
  fold the outline, which is not something to do to somebody by accident.

Fixed

• Pointer movement redrew the reader, for nothing. Asking a terminal to
  report the mouse asked it, through crossterm, for any-event tracking as well
  as the wheel — a report per cell the pointer crossed, each one a wakeup, a
  re-layout and a whole frame drawn and diffed away, for as long as a hand
  rested on the mouse. Nothing here has ever read a mouse column. The reader
  now asks for the wheel and nothing else, and drops the rest on arrival in
  case it was asked anyway.

• Mouse tracking left on by another program is now turned off on the way
  in. An editor opened with e and then killed leaves it on for good, and
  the reader it comes back to had no way to know: it would report every pointer
  movement into a program with no use for a mouse at all.

• A README key table ran past its own end on Windows. The doc-drift scan
  split on a blank line, which a CRLF checkout does not contain, so every
  table continued to the end of the file and fed the chord parser whatever
  backticks it met. Nothing after the key tables had a backticked cell in its
  first column until now, which is why it had never shown.

Notes

The question and its answer travel the same stream as keystrokes, and reading
is destructive. So the exchange happens once, before the screen is taken and
before the thread that owns standard input exists; on /dev/tty rather than
either standard stream; declined outright if anything is already queued; and
ended by a device-attributes sentinel rather than by the clock. Only system
asks at all.

Windows falls back for now: the replies arrive there through the console input
API rather than as bytes on a device, which is a different mechanism rather
than a variation on this one.

registry::resolve takes what the terminal answered in place of its old
Option<bool>, and registry::Origin has gained a variant and become
#[non_exhaustive]. Both are in the stable half of the API, which is what
makes this 0.6.0 rather than 0.5.2.