fix(bot): close dialog engine gaps (C-SSRS repeat, scale intros, button payloads, step timeout)

- No same-day C-SSRS repeat: a risk screen completed within cssrs_cooldown_hours is not queued again
  after PHQ-9 item 9 >= 1 (scale crisis path, rule schedule_scale, scale_due); crisis script and alerts stay.
- Scale intro registry: register_scale_intro(scale_id, text_or_fn); start_scale(intro=None) uses it.
  veteran_daily migrated from per-scale on_enter hooks.
- Prefix triggers "button:<prefix>:*" with trigger_payload(event); medication buttons carry the dose
  (med:taken:<dose_id>, ...), med_pending dropped; payload-less legacy buttons answer as stale.
- Abandoned-step timeout: settings.abandon_after_hours (default 6 h) returns abandonable states
  (daily.*, meds.*, scale.* not in onboarding) to idle before the next event; never in crisis or with intake on.

Refs #56

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

app/dialog/flows/veteran_daily.py

@@ -24,14 +24,14 @@ Data algorithm (medical data, jury requirement):
     alcohol interaction, visit offer) come from the rules through `MonitoringService` (ADR-007).
   * A free-text message classified POSSIBLE by the safety layer is taken over by the engine (C-SSRS). When the
     screen returns to `daily.text` the message counts as the answer: the check-in is closed, not asked again.
-  * A check-in left unfinished is dropped on the next system event of a later day.
+  * A check-in left unfinished is dropped on the next event of a later day, or after
+    `settings.abandon_after_hours` of silence (engine abandon timeout, #56) — answers given so far stay stored.
 
-Also here: friendly intros for scheduled scales (pcl5, phq9, dar5, auditc) — the engine starts `scale_due`
-scales without an intro, so an exact `scale.<id>` enter hook adds one and delegates to the generic scale hook.
+Also here: friendly intros for scheduled scales (pcl5, phq9, dar5, auditc), registered with
+`register_scale_intro` so the engine's `scale_due` / rule-triggered sessions show them.
 """
 
 import re
-from dataclasses import replace
 from datetime import datetime
 from functools import lru_cache
 from pathlib import Path
@@ -59,9 +59,8 @@ from app.dialog.flows.meds import (
     save_checkin,
     side_effect_reply,
 )
-from app.dialog.fsm import Ctx, Step, enter_hook_for, on_enter, state, trigger
-from app.dialog.scale_session import PREFIX as SCALE_PREFIX
-from app.dialog.scale_session import active_scale, scale_state
+from app.dialog.fsm import Ctx, Step, abandonable, on_enter, state, trigger
+from app.dialog.scale_session import register_scale_intro
 
 PREFIX = "daily"
 STEPS = ("mood", "med", "sleep", "nightmares", "alcohol", "text")
@@ -346,6 +345,9 @@ async def _free_text(ctx: Ctx, ck: dict[str, Any]) -> Step:
     return _finish(ctx, replies)
 
 
+abandonable(PREFIX)
+
+
 @state(PREFIX)
 async def _handle(ctx: Ctx, event: Event) -> Step:
     step = ctx.state.split(".", 1)[1] if "." in ctx.state else ""
@@ -451,30 +453,13 @@ async def _idle_text(ctx: Ctx, event: Event) -> Step:
 # ------------------------------------------------------------------------------------------- scale intros
 
 
-async def _scale_intro(ctx: Ctx) -> Step:
-    """Add the friendly intro of a scheduled (or rule-triggered) scale, then run the generic scale enter hook.
-
-    Onboarding sessions (#36) and sessions started with their own intro are left untouched.
-    """
-    scale_id = active_scale(ctx.state)
-    sessions = dict(ctx.data.get("scales") or {})
-    session = sessions.get(scale_id) if scale_id else None
-    if (
-        scale_id is not None
-        and session is not None
-        and session.get("idx") == 0
-        and not session.get("intro_shown")
-        and not session.get("intro")
-        and ".onboarding" not in str(session.get("return_state", ""))
-    ):
-        intros = load_daily_texts().scale_intros
-        intro = (intros.scheduled if session.get("scheduled", True) else intros.unscheduled).get(scale_id)
-        if intro:
-            sessions[scale_id] = {**session, "intro": intro}
-            ctx = replace(ctx, data={**ctx.data, "scales": sessions})
-    generic = enter_hook_for(SCALE_PREFIX)
-    return await generic(ctx) if generic is not None else Step()
+def _scale_intro(ctx: Ctx, scale_id: str, scheduled: bool, return_state: str) -> str | None:
+    """Friendly intro of a scheduled (or rule-triggered) scale. Onboarding sessions (#36) have their own texts."""
+    if ".onboarding" in return_state:
+        return None
+    intros = load_daily_texts().scale_intros
+    return (intros.scheduled if scheduled else intros.unscheduled).get(scale_id)
 
 
 for _scale_id in load_daily_texts().settings.intro_scales:
-    on_enter(scale_state(_scale_id))(_scale_intro)
+    register_scale_intro(_scale_id, _scale_intro)