feat(client): move-here path preview + RMB gesture vocabulary (T-1088, Q-084)

Hover marker + optimal path line over the KNOWN tile store only — the
character plans through what they know; fog is unpathable (info boundary at
the planning layer; the follower additionally revalidates every remaining
tile per step). Pure static 8-dir A*: uniform cost 1 incl. diagonals (D-248
time-optimal, no sqrt2), no corner-cutting, terrain-cost provider seam for
Phase-4 terrain. Execution streams ordinary Move* steps through the existing
throttle — zero protocol change, server validates every step.

RMB vocabulary (live-session spec): click = walk there at current stance;
double-click = sprint there (ToggleStanceUp burst — server toggle handler
verified cooldown-free so bursts climb deterministically — with net-zero
restore on arrival; a double upgrades the active follow in place);
long-press >=400ms = go there then Crouch on arrival, no restore (input-
vocabulary prototype; real cover mechanics are future combat design).
Cancellation: WASD override (stance kept), invalidation, teleport,
suppression. Two additive InputMapper seams (queue_move_step,
queue_stance_toggle); mouse unproject shared with the facing provider
(ground_hit_local). 44 new gdUnit tests across finder + follower ladders.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

client/scripts/autoloads/input_mapper.gd

@@ -175,6 +175,50 @@ func flush_queue() -> Array[Dictionary]:
 	return queue
 
 
+# T-1088 click-to-move seam (design §9 / D-248): queue ONE 8-direction step from a
+# sim tile delta (e.g. Vector2i(1, 0) = East, Vector2i(1, 1) = Southeast), gated by
+# the SAME per-stance throttle held-WASD uses (_last_move_msec + MOVE_INTERVAL_MS).
+# The sandbox path follower calls this once per frame while walking a client-planned
+# path; the shared throttle paces it to the exact stance cadence (no duplicated
+# interval table) and interleaves cleanly with WASD — a held key and a queued step
+# can never both fire inside one window. Returns true when the step was queued,
+# false when throttled or input-suppressed. Ordinary Move* actions only: zero
+# protocol change, no client prediction, the server validates every step (D-010).
+func queue_move_step(tile_delta: Vector2i) -> bool:
+	if GameState.dialogue_active or GameState.free_camera_mode:
+		return false
+	if tile_delta == Vector2i.ZERO:
+		return false
+	var now := Time.get_ticks_msec()
+	var interval: int = MOVE_INTERVAL_MS.get(GameState.player_stance, 200)
+	if now - _last_move_msec < interval:
+		return false
+	_last_move_msec = now
+	input_queue.append(
+		{
+			"action": _dir_to_action(tile_delta),
+			"timestamp_msec": now,
+		}
+	)
+	return true
+
+
+# T-1088 double-RMB sprint-there seam: queue ONE ordinary stance toggle (up = toward
+# Sprint, down = toward Crouch) through the same input_queue movement rides. Discrete,
+# so no throttle — the server's handle_toggle_stance has no cooldown, so the sandbox
+# follower can burst the exact ladder distance and trust it (server validates). No-op
+# while input is suppressed (dialogue / free camera), matching movement.
+func queue_stance_toggle(up: bool) -> void:
+	if GameState.dialogue_active or GameState.free_camera_mode:
+		return
+	input_queue.append(
+		{
+			"action": Action.TOGGLE_STANCE_UP if up else Action.TOGGLE_STANCE_DOWN,
+			"timestamp_msec": Time.get_ticks_msec(),
+		}
+	)
+
+
 ## Reset facing state to default (North). Use in tests per D-030 testability.
 func reset_facing_state() -> void:
 	facing_angle = -PI / 2.0