fix: match the compact edition markers a cover carries

"Building Microservices, 2E" never matched "Building Microservices". Key the
strip on the trailing "e" so 2E, 5e and 3 Ed are caught, while a bare number
leaves "Catch 22" and "Blade Runner 2049" alone. Stored keys are recomputed.

backend/migrations/versions/2026-08-15_recompute_book_matching_keys_ed41acf21270.py

@@ -0,0 +1,126 @@
+"""recompute book matching keys
+
+Revision ID: ed41acf21270
+Revises: 4358e7d4743a
+Create Date: 2026-08-15 15:44:28.341020
+
+"""
+
+import warnings
+from typing import TYPE_CHECKING
+
+import sqlalchemy as sa
+from alembic import op
+from advanced_alchemy.types import EncryptedString, EncryptedText, GUID, ORA_JSONB, DateTimeUTC, StoredObject, PasswordHash, FernetBackend
+from advanced_alchemy.types.encrypted_string import PGCryptoBackend
+from advanced_alchemy.types.password_hash.argon2 import Argon2Hasher
+from advanced_alchemy.types.password_hash.passlib import PasslibHasher
+from advanced_alchemy.types.password_hash.pwdlib import PwdlibHasher
+from sqlalchemy import Text  # noqa: F401
+
+if TYPE_CHECKING:
+    from collections.abc import Sequence
+
+__all__ = ["downgrade", "upgrade", "schema_upgrades", "schema_downgrades", "data_upgrades", "data_downgrades"]
+
+sa.GUID = GUID
+sa.DateTimeUTC = DateTimeUTC
+sa.ORA_JSONB = ORA_JSONB
+sa.EncryptedString = EncryptedString
+sa.EncryptedText = EncryptedText
+sa.StoredObject = StoredObject
+sa.PasswordHash = PasswordHash
+sa.Argon2Hasher = Argon2Hasher
+sa.PasslibHasher = PasslibHasher
+sa.PwdlibHasher = PwdlibHasher
+sa.FernetBackend = FernetBackend
+sa.PGCryptoBackend = PGCryptoBackend
+
+# revision identifiers, used by Alembic.
+revision = 'ed41acf21270'
+down_revision = '4358e7d4743a'
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    with warnings.catch_warnings():
+        warnings.filterwarnings("ignore", category=UserWarning)
+        with op.get_context().autocommit_block():
+            schema_upgrades()
+            data_upgrades()
+
+def downgrade() -> None:
+    with warnings.catch_warnings():
+        warnings.filterwarnings("ignore", category=UserWarning)
+        with op.get_context().autocommit_block():
+            data_downgrades()
+            schema_downgrades()
+
+def schema_upgrades() -> None:
+    """schema upgrade migrations go here."""
+    pass
+
+def schema_downgrades() -> None:
+    """schema downgrade migrations go here."""
+    pass
+
+def data_upgrades() -> None:
+    """
+    Recompute every matching key against the current normalization.
+
+    The keys are derived, so changing a helper in `services/matching.py` silently
+    invalidates every row already written — a book stored under the old rules simply
+    stops matching one stored under the new ones, with nothing to show that anything
+    is wrong. `normalize_title` learned to strip the compact edition markers a cover
+    actually carries ("2E", "5e"), which moved `Building Microservices, 2E` onto the
+    same key as `Building Microservices`.
+
+    Any later change to those helpers wants a revision that looks exactly like this
+    one. It is idempotent and safe to re-run.
+    """
+    from chitai.services.matching import (
+        normalize_author,
+        normalize_identifier,
+        normalize_title,
+    )
+
+    connection = op.get_bind()
+
+    books = connection.execute(sa.text("SELECT id, title FROM books")).fetchall()
+    _apply(
+        connection,
+        "UPDATE books SET normalized_title = :key WHERE id = :id",
+        [{"id": id, "key": normalize_title(title)} for id, title in books],
+    )
+
+    authors = connection.execute(sa.text("SELECT id, name FROM authors")).fetchall()
+    _apply(
+        connection,
+        "UPDATE authors SET normalized_name = :key WHERE id = :id",
+        [{"id": id, "key": normalize_author(name)} for id, name in authors],
+    )
+
+    identifiers = connection.execute(
+        sa.text("SELECT id, name, value FROM identifiers")
+    ).fetchall()
+    _apply(
+        connection,
+        "UPDATE identifiers SET normalized_value = :key WHERE id = :id",
+        [
+            {"id": id, "key": normalize_identifier(name, value)}
+            for id, name, value in identifiers
+        ],
+    )
+
+
+def _apply(connection, statement: str, parameters: list[dict]) -> None:
+    """Run one update per row, in batches, skipping the work when there are none."""
+    batch_size = 1000
+
+    for start in range(0, len(parameters), batch_size):
+        connection.execute(sa.text(statement), parameters[start : start + batch_size])
+
+
+def data_downgrades() -> None:
+    """Add any optional data downgrade migrations here!"""