Completes the humanize suite:
- Clicks land on a jittered point inside the element's box (Fast/Human) instead
of its exact centre. `resolve_element_center` now also returns the element
width/height (box_model_dims); the CSS-selector path reports zero size → land
on centre (no jitter, no regression). Jitter is clamped to the inner box so the
click never misses.
- Wheel scrolls split into eased, jittered segments (humanize::scroll_segments,
unit-tested) instead of one instant jump.
- Drag follows the curved trajectory at Fast/Human (linear 10-step at Off).
Off is unchanged throughout. 9/9 unit tests; verified headless — jittered click
still lands (→ iana.org), segmented scroll moves the page.
Behavioural stealth: a click that teleports the cursor to an element's exact
centre with no approach path and zero press/release delay is a tell that
advanced anti-bot vendors (Akamai/PerimeterX/DataDome) flag, even though our CDP
events are isTrusted.
New `native::humanize` module — pure, unit-tested motion maths (cubic-Bézier
eased trajectories, in-bounds landing jitter, variable keystroke cadence, and an
anti-bot vendor detector) plus a small daemon-wide runtime (current level + last
cursor + per-action seed). `dispatch_click` now moves along a curved,
decelerating path from the last cursor position and dwells before releasing.
Three levels off|fast|human. Default is Off → byte-for-byte the old teleport, so
nothing changes until opted in. `AGENT_BROWSER_HUMANIZE=human` forces it now;
the adaptive per-navigation detector (set_detected_level) and type/wheel/drag
coverage land next. 8/8 unit tests; fmt + clippy clean.