Fix SQLiteException crash in MIGRATION_5_6 from unescaped apostrophes

[troymyree-lang]

Summary

• MIGRATION_5_6 built its Phrase_New/Category_New INSERT statements via raw string interpolation, so an apostrophe in user-generated text ("I'm hungry", "It's my turn") broke the SQL statement and threw SQLiteException inside Room's onUpgrade -- blocking the database, and the app, from ever opening for affected users
• Switched both INSERT statements to parameterized queries (bind args instead of string interpolation), which also fixes a related defect where a null value was written as the literal string "null" instead of a true SQL NULL
• Added a regression test seeding a v5 database with an apostrophe in both a user-generated phrase and a category name, confirming the migration now succeeds and the text round-trips correctly

Ticket

Closes #698

Type of Change

• Bug fix
• Tests

Testing

• Unit tests added/updated
• Integration tests added/updated
• Manual testing performed

New instrumented test (migrate5to6_preservesApostropheInUserGeneratedText in MigrationTest.kt) wasn't run against a device/emulator locally (none available in this environment) -- it will run via Firebase Test Lab in CI along with the rest of androidTest. compileDebugKotlin, compileDebugAndroidTestKotlin, and testDebug (all JVM unit tests) verified passing locally.

Checklist

• Tests pass locally (./gradlew testDebug)
• No API keys or secrets in code
• CLAUDE.md updated (if new pattern introduced) -- not needed, no new pattern introduced