refactor: move fork-only migrations to migrations_fork.py

`migrations.py` now matches upstream v1.3.0 exactly. Every aio-only
schema delta (the old m007-m011: user_id, status, nostr_event_id +
created_at, settings table, location + categories) moves into a
single `m001_aio_event_schema` function in `migrations_fork.py`,
tracked under `events_fork` in `dbversions` by the loader added in
aiolabs/lnbits@ae997181.

Idempotency guards on every ADD COLUMN / CREATE TABLE let the
squashed migration no-op cleanly on dev DBs that already ran the
old m007-m011 — schema lands identical from either path.

Why now: aiolabs/lnbits#8. We're about to rebase events onto
upstream v1.6.1 which adds its own m007_add_allow_fiat. With this
move done first, migrations.py stays a fast-forward on rebase and
our fork-only schema lives in a separate file that never collides.

Requires aiolabs/lnbits @ ae997181 or later for the extension_fork
loader. Running on an upstream lnbits without the loader patch
will NOT apply the fork schema — but the aiolabs deploy fleet
already pulls from aiolabs/lnbits, so this is the only host we
ship to.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

migrations.py

@@ -162,96 +162,16 @@ async def m005_add_image_banner(db):
     await db.execute("ALTER TABLE events.events ADD COLUMN banner TEXT;")
 
 
-async def _alter_add_column_safe(db, sql: str) -> None:
-    """ALTER TABLE ADD COLUMN that swallows duplicate-column errors.
-
-    Earlier aiolabs/events forks added some of these columns under different
-    migration names (e.g. our former m007). Skipping the error keeps the
-    migration log monotonic for both fresh installs and pre-rebase upgrades.
-    """
-    try:
-        await db.execute(sql)
-    except Exception as exc:
-        msg = str(exc).lower()
-        if "duplicate column" in msg or "already exists" in msg:
-            return
-        raise
-
-
 async def m006_add_extra_fields(db):
     """
     Add a canceled and 'extra' column to events and ticket tables
     to support promo codes and ticket metadata.
     """
-    await _alter_add_column_safe(
-        db,
-        "ALTER TABLE events.events ADD COLUMN canceled BOOLEAN NOT NULL DEFAULT FALSE",
-    )
-    await _alter_add_column_safe(db, "ALTER TABLE events.events ADD COLUMN extra TEXT")
-    await _alter_add_column_safe(db, "ALTER TABLE events.ticket ADD COLUMN extra TEXT")
-
-
-async def m007_add_user_id_support(db):
-    """
-    Add user_id column to ticket table so a ticket can reference an LNbits
-    user id instead of (name, email). Application logic enforces that exactly
-    one identifier scheme is used per ticket.
-    """
-    await _alter_add_column_safe(
-        db, "ALTER TABLE events.ticket ADD COLUMN user_id TEXT"
-    )
-
-
-async def m008_add_event_status(db):
-    """
-    Add status column to events table for the proposal/approval workflow.
-    Values: 'proposed', 'approved', 'rejected'. Existing rows default to
-    'approved' so they stay visible after upgrade.
-    """
-    await _alter_add_column_safe(
-        db,
-        "ALTER TABLE events.events ADD COLUMN status TEXT NOT NULL DEFAULT 'approved'",
-    )
-
-
-async def m009_add_nostr_columns(db):
-    """
-    Track the most recent NIP-52 calendar event we published for this event
-    (used for replaceable updates and NIP-09 deletes).
-    """
-    await _alter_add_column_safe(
-        db, "ALTER TABLE events.events ADD COLUMN nostr_event_id TEXT"
-    )
-    await _alter_add_column_safe(
-        db, "ALTER TABLE events.events ADD COLUMN nostr_event_created_at INTEGER"
-    )
-
-
-async def m010_add_events_settings(db):
-    """
-    Create the extension settings singleton row used by the admin UI to
-    toggle e.g. auto_approve.
-    """
-    await db.execute("""
-        CREATE TABLE IF NOT EXISTS events.settings (
-            id INTEGER PRIMARY KEY DEFAULT 1,
-            auto_approve BOOLEAN NOT NULL DEFAULT FALSE
-        )
-        """)
+    # Add canceled and 'extra' columns to events table
     await db.execute(
-        "INSERT INTO events.settings (id, auto_approve) "
-        "SELECT 1, FALSE WHERE NOT EXISTS "
-        "(SELECT 1 FROM events.settings WHERE id = 1)"
+        "ALTER TABLE events.events ADD COLUMN canceled BOOLEAN NOT NULL DEFAULT FALSE;"
     )
+    await db.execute("ALTER TABLE events.events ADD COLUMN extra TEXT;")
 
-
-async def m011_add_location_and_categories(db):
-    """
-    Add NIP-52 calendar metadata (location and a JSON-encoded category list).
-    """
-    await _alter_add_column_safe(
-        db, "ALTER TABLE events.events ADD COLUMN location TEXT"
-    )
-    await _alter_add_column_safe(
-        db, "ALTER TABLE events.events ADD COLUMN categories TEXT"
-    )
+    # Add 'extra' column to ticket table
+    await db.execute("ALTER TABLE events.ticket ADD COLUMN extra TEXT;")