refactor: rename package fabledassistant -> scribe (code-only)

Renames src/fabledassistant -> src/scribe and all imports, plus the
default DB name and DB user/password (fabled -> scribe) in config +
compose. 952 refs / 154 files. Reverses the old 'internal name stays
fabledassistant' convention.

Code-only: live databases are still physically named 'fabledassistant'.
Deployed environments must set POSTGRES_DB / POSTGRES_USER (or rename the
DB) since the defaults now resolve to 'scribe'. Repo (FabledScribe), git
host (fabledsword), MCP (fabled-git) and the image name (fabledscribe)
are intentionally unchanged.

ruff check src/ clean locally; CI (typecheck + pytest) is the gate.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/scribe/services/tz.py

@@ -0,0 +1,52 @@
+"""User-timezone helpers.
+
+All datetimes in the DB are stored as UTC. The helpers here bridge between
+that UTC storage and the user's configured local timezone (IANA string in
+the ``user_timezone`` setting). Use these anywhere the model or UI talks
+in terms of "today", "tomorrow", or a bare calendar date — never
+``date.today()`` or ``datetime.now(timezone.utc)`` inside a per-user flow.
+"""
+from __future__ import annotations
+
+from datetime import date, datetime, timedelta
+from zoneinfo import ZoneInfo, ZoneInfoNotFoundError
+
+from scribe.services.settings import get_setting
+
+# Day-rollover boundary for journal/day-anchored views. The "day" flips at
+# this local hour (not midnight) so the 00:00–04:00 local window still
+# shows yesterday's content until the user "starts" the new day.
+DAY_ROLLOVER_HOUR = 4
+
+# Backwards-compat alias for code paths still referencing the old name.
+BRIEFING_DAY_START_HOUR = DAY_ROLLOVER_HOUR
+
+
+async def get_user_tz(user_id: int) -> ZoneInfo:
+    """Return the user's IANA ``ZoneInfo``, falling back to UTC."""
+    tz_str = await get_setting(user_id, "user_timezone") or "UTC"
+    try:
+        return ZoneInfo(tz_str)
+    except (ZoneInfoNotFoundError, KeyError):
+        return ZoneInfo("UTC")
+
+
+async def user_today(user_id: int) -> date:
+    """Return today's calendar date in the user's local timezone."""
+    tz = await get_user_tz(user_id)
+    return datetime.now(tz).date()
+
+
+async def user_day_date(user_id: int) -> date:
+    """Return the current "day" in the user's local timezone.
+
+    The day flips at ``DAY_ROLLOVER_HOUR`` (4am local) rather than midnight,
+    so the 00:00–04:00 local window still returns *yesterday* — the user's
+    journal stays anchored to yesterday until they cross the rollover.
+    """
+    tz = await get_user_tz(user_id)
+    return (datetime.now(tz) - timedelta(hours=DAY_ROLLOVER_HOUR)).date()
+
+
+# Backwards-compat alias used by briefing-only modules being torn down in Stage B.
+user_briefing_date = user_day_date