Lets an external reader (sqlite3 CLI, DB Browser, DataGrip) inspect the
database file concurrently without "database is locked" errors while
geniusrund is running. Doesn't change in-process concurrency -- queries
are already fully serialized via SetMaxOpenConns(1).
auth: fix flaky tampered-cookie tests
Both tests corrupted a signed cookie by blindly overwriting its last
character with "x", which is occasionally a no-op if that character (part
of the token's signature, so effectively randomized by the embedded
timestamp) already happened to be "x" -- silently passing without having
tampered with anything. Confirmed via 15 repeated runs (3 spurious passes)
before the fix and 30 clean runs after. flipLastChar now guarantees the
byte actually changes.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
