fix(rules): allow a staggered creature to withdraw as a standard action

SRD 'Full-Round Actions - Restricted Withdraw': 'If you are limited to taking only a standard action each round you can withdraw as a standard action. In this case, you may move up to your speed.' _staggered_filter now keeps withdraw as the one move-or-standard action (spending the slot) instead of dropping it, and _flee_path halves the budget to single speed for a staggered/disabled creature (new _is_staggered_limited helper). Filter-level and engine-level tests added.

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

README.md

@@ -735,12 +735,18 @@ Règles modélisées :
   ligne droite doit être dégagée (pas de terrain difficile, d'obstacles ni de
   créatures) ; distance minimum 2 cases (10 ft). `default_policy` choisit la
   charge quand l'ennemi est hors de portée mais joignable en ligne droite.
-- Retraite : action à round complet. Le combattant se déplace jusqu'à 2× sa
+ - Retraite : action à round complet. Le combattant se déplace jusqu'à 2× sa
    vitesse en s'éloignant de l'ennemi le plus proche (ascension gloutonne du
    champ de coût Dijkstra depuis la menace). La case de départ n'est pas
    considérée comme menacée — aucune AoO en la quittant. Les cases
    ultérieures provoquent des AoO normalement (résolues pas à pas, comme pour
-  le mouvement). `default_policy` ne choisit pas la retraite (disponible via
+   le mouvement). Conformance L6 (SRD « Full-Round Actions — Restricted
+   Withdraw ») : « If you are limited to taking only a standard action each
+   round you can withdraw as a standard action. In this case, you may move up
+   to your speed » — un combattant `staggered`/invalidé qui reçoit `withdraw`
+   le conserve comme **action standard** (le filtre staggered ne le jette
+   plus) avec un budget de **1× vitesse** au lieu de 2× (`_flee_path` via
+   `_is_staggered_limited`). `default_policy` ne choisit pas la retraite (disponible via
    une politique personnalisée).
 - Course (`Action(kind="run")`, action à round complet, U5e) : le combattant
   se déplace jusqu'à **4× sa vitesse** vers `target_id` (auto-dirigé,

src/pf1e_simulator/combat.py

@@ -1641,7 +1641,7 @@ class CombatEngine:
             )
             actions = kept
             state.immediate_used = False
-        if self._is_disabled(state) or self._has_condition_named(state, "staggered"):
+        if self._is_staggered_limited(state):
             kept = _staggered_filter(actions, cast_time=self._cast_time_of)
             results.extend(
                 ActionResult(kind=kind, ok=False, reason=_REASON_DOWNGRADED_STAGGERED)
@@ -1677,6 +1677,16 @@ class CombatEngine:
         disabled — staggered, half speed, and a strenuous action costs 1 hp."""
         return state.hp == 0
 
+    def _is_staggered_limited(self, state: CombatantState) -> bool:
+        """True when the creature is limited to one move OR one standard
+        action per round (CRB "Conditions — Staggered"; a disabled creature
+        at 0 hp is staggered). Such a creature cannot take full-round actions
+        — except Restricted Withdraw (SRD "Full-Round Actions"), which it may
+        take as a standard action moving up to its speed."""
+        return self._is_disabled(state) or self._has_condition_named(
+            state, "staggered"
+        )
+
     def _is_helpless(self, state: CombatantState) -> bool:
         """PF1e (CRB): helpless = paralyzed, held, bound, sleeping, unconscious.
 
@@ -6479,11 +6489,18 @@ class CombatEngine:
     def _flee_path(self, state: CombatantState, threat: CombatantState) -> list[Pos]:
         """Movement path away from ``threat``, up to double speed.
 
+        A staggered/disabled creature taking Restricted Withdraw (SRD "Full-Round
+        Actions": "you can withdraw as a standard action. In this case, you may
+        move up to your speed") gets a single-speed budget instead.
+
         Uses the Dijkstra cost field from the threat and greedily picks the
         step that maximizes distance (cost) from the threat each cell.
         """
         speed_mult = self._get_speed_mult(state)
-        max_cells = int(2 * (_speed_ft(state) // _SQUARE_FT) * speed_mult)
+        withdraw_mult = 1 if self._is_staggered_limited(state) else 2
+        max_cells = int(
+            withdraw_mult * (_speed_ft(state) // _SQUARE_FT) * speed_mult
+        )
         if max_cells <= 0:
             return []
         blocked = self._blocked(state)
@@ -6537,6 +6554,10 @@ class CombatEngine:
     def _withdraw(self, state: CombatantState, threat: CombatantState | None) -> None:
         """Full-round action: move up to 2x speed away from the nearest enemy.
 
+        Restricted Withdraw (SRD "Full-Round Actions"): a staggered/disabled
+        creature takes this as a standard action and moves up to its speed
+        (single, not double — see ``_flee_path``).
+
         The starting square is not threatened — no AoO when leaving it.
         Subsequent squares provoke AoOs normally (step-by-step, as for move).
         Like every other movement it is mutually exclusive with movement
@@ -6821,8 +6842,12 @@ def _staggered_filter(
     and drops full-round actions plus any SECOND move-or-standard. A leading
     ``full_attack`` (already in range) is downgraded to a single standard
     ``attack`` that consumes the one move-or-standard slot; a further
-    full-round action (charge, withdraw, run, a full-round/one-round cast,
+    full-round action (charge, run, a full-round/one-round cast,
-    spell_combat) is dropped.
+    spell_combat) is dropped. Exception (SRD "Full-Round Actions — Restricted
+    Withdraw"): "If you are limited to taking only a standard action each
+    round you can withdraw as a standard action. In this case, you may move
+    up to your speed" — a ``withdraw`` is kept as the one standard action and
+    ``_flee_path`` halves its budget to single speed.
     """
     kept: list[Action] = []
     slot_used = False  # the single move-OR-standard slot is spent
@@ -6836,6 +6861,10 @@ def _staggered_filter(
             continue
         slot = _effective_slot(action, cast_time)
         if slot == "full_round":
+            if action.kind == "withdraw" and not slot_used:
+                # Restricted Withdraw: standard action, move up to speed.
+                kept.append(action)
+                slot_used = True
             continue
         if slot in ("standard", "move"):
             if slot_used:

tests/test_conditions_effects.py

@@ -7,7 +7,7 @@ Part (b): Condition behavioral effects enforced via action economy / AC modifier
 
 from __future__ import annotations
 
-from pf1e_simulator.combat import CombatantState, CombatEngine
+from pf1e_simulator.combat import Action, CombatantState, CombatEngine
 from pf1e_simulator.conditions import NAUSEATED, PARALYZED, PRONE, STAGGERED
 from pf1e_simulator.dice import parse_dice
 from pf1e_simulator.effects import ActiveCondition, StatModifier
@@ -188,6 +188,42 @@ class TestStaggeredActionEconomy:
         result = engine._take_turn(h)
         assert result is False
 
+    def test_staggered_restricted_withdraw_moves_single_speed(self) -> None:
+        # SRD "Full-Round Actions — Restricted Withdraw": "If you are limited
+        # to taking only a standard action each round you can withdraw as a
+        # standard action. In this case, you may move up to your speed" — 30
+        # ft = 6 cells, not the 2x full-round budget.
+        legend = {".": TerrainType(type="floor", move_cost=1)}
+        grid = Grid.from_spec(
+            MapSpec(name="big", terrain=tuple(["." * 20] * 20), legend=legend)
+        )
+        hero = _make_hero()
+        foe = _make_foe()
+        h = CombatantState(combatant=hero, side="players", pos=(10, 10), hp=hero.hp_max)
+        f = CombatantState(combatant=foe, side="monsters", pos=(10, 9), hp=foe.hp_max)
+        h.active_conditions.append(
+            ActiveCondition(condition=STAGGERED, rounds_left=5, source="test")
+        )
+        engine = CombatEngine(
+            ScriptedRng([10, 9]),
+            grid,
+            [h, f],
+            round_cap=1,
+            policy=lambda _e, s: (
+                (Action(kind="withdraw", target_id="foe"),)
+                if s.combatant.id == hero.id
+                else (Action(kind="wait"),)
+            ),
+        )
+        engine.run()
+        withdraw_lines = [
+            line for line in engine._transcript if "withdraw" in line
+        ]
+        assert len(withdraw_lines) == 1
+        # 6 steps from (10,10) — exactly the single-speed budget.
+        assert withdraw_lines[0].count("->") == 6
+        assert h.pos != (10, 10)
+
 
 # ── Test 4: nauseated → single move action only ───────────────────────────────
 

tests/test_conformance_action_economy.py

@@ -350,6 +350,18 @@ def test_staggered_filter_drops_full_round_and_downgrades_full_attack() -> None:
     assert _staggered_filter((_foe("move"), _foe("full_attack"))) == (_foe("move"),)
 
 
+def test_staggered_filter_keeps_withdraw_as_restricted_standard() -> None:
+    # SRD "Full-Round Actions — Restricted Withdraw": a creature limited to a
+    # standard action each round may withdraw as a standard action (moving up
+    # to its speed) — the staggered filter keeps it and spends the slot.
+    assert _staggered_filter((_foe("withdraw"),)) == (_foe("withdraw"),)
+    # After the one move-or-standard slot is spent, withdraw is dropped.
+    assert _staggered_filter((_foe("attack"), _foe("withdraw"))) == (_foe("attack"),)
+    assert _staggered_filter((_foe("move"), _foe("withdraw"))) == (_foe("move"),)
+    # A leading withdraw spends the slot; the following standard is dropped.
+    assert _staggered_filter((_foe("withdraw"), _foe("attack"))) == (_foe("withdraw"),)
+
+
 def test_nauseated_after_budget_keeps_single_move() -> None:
     # (move, attack, move): the budget drops the second move; the nauseated
     # filter then keeps only the first move and drops the standard attack.