io.github.risyadul/lionscope

### Added

- Agent tool `mark` (session): names the current moment of the running session, e.g. `run-3` before the third
  repetition of a test. `search_logcat` and `get_crashes` take `sinceMarker` (instead of `since`) and
  `untilMarker`, so lines and crashes can be counted per run without clock math or clearing the device's log
  buffer; a range that ends before it starts is refused. Markers are on the clock logcat lines are timed on (the
  device clock plus the offset measured at the session start); marking a label again moves it, `status` lists the
  newest 20 and a new session starts without any. They are not shown in the dashboard.
- `search_logcat` and `get_crashes` return the resolved time `range`, and `search_logcat` `complete`: false once
  lines of that range have been dropped from the log buffer, so a count taken too late does not read as zero.
- `screenshot` returns `meanLuminance`, `nonBlackRatio`, `dominantRatio` and `blank` of the full-size capture, to
  tell across runs whether a screen rendered or stayed black without comparing images: `blank` means one colour
  covers at least 98% of the pixels, all near-black shades counting as one (a black video area with only status
  bar icons on top, also a sparse page of any colour). The image is unchanged; a capture that can't be decoded
  gets null numbers.
- Agent tool `stop_app` (device control): force-stops an app with `am force-stop`, for a clean run without starting
  it again (`launch_app` with `cold` only stops it to start it). Its unsaved state is lost, unlike pressing HOME.
- `hint` selector for `tap_element`, `type_text`'s `field`, `wait_for` and `scroll_to`: a field's hint (placeholder)
  as `get_ui_tree` lists it. Where the dump has hints, it keeps matching once the field has text, unlike `text` (an
  empty field reports its hint as its text). Where it has none (older Android versions), it matches the text of any
  editable field instead, so it finds an empty field by its hint but not a filled one.
- `type_text` `mode`: `cursor` (the default, as before: text goes in at the caret, which lands where the tap
  landed), `append` (the caret goes to the end of the text first) and `replace` (the field's text is deleted
  first); `replace` with `text: ""` clears the field. Both need a focused text field, read from a new dump before
  any key: the one given as `field` must have taken the focus (one that opens a picker instead gets no key), and
  without `field` the focused one is used. An empty field gets no keys. Android 13+ gets ctrl+End, or ctrl+A and
  Delete (`input keycombination`). Older versions, or a device whose version can't be read, have no ctrl key from
  adb: `append` presses End, which reaches the end of the caret's line only in a multi-line field, and `replace`
  deletes as many characters as the UI tree shows (End then Delete, or Delete and Forward delete around the caret
  when the text has line breaks), so it refuses a password field, whose text the tree hides. In a multi-line field
  whose text wraps without line breaks, part of it may stay (the dump does not say a field is multi-line);
  `matches` then says `false`.
- Agent tool `get_crashes`: the app's crashes since the session started, read from logcat's `crash` buffer (the
  package's process and its `<package>:*` processes, not just the PID being followed), so a crash is kept even when
  the app's own logcat turns over within a minute, when the process died before Lionscope saw its PID (a
  start-and-crash loop), and for the app's other processes (`:remote`). Uncaught Java/Kotlin exceptions
  (`FATAL EXCEPTION`) and native crashes (crash_dump's report: signal, cause, abort message, backtrace), the last 50
  per session, with time, pid, thread, process, exception and message, and the stack (every `Caused by`, the first
  12 frames of each exception). Stored redacted; other apps' crash lines are passed over and never stored.
- `search_logcat` returns `retained` (`entries`, `capacity`, `oldes