D048 - Per-title files, merged per key

Status: decided Date: 2026-09-26

Title-specific behaviour lives in one file per title, identified by a hash of its executable, never in code. Layers merge per key, user over repository over global. A compatibility key names a deviation, not a title, prefers a typed value to a boolean, and carries a reason and a label: quirk, workaround or unsupported. Every applied override is reported in the run.

Why: a key named for the behaviour lets a second title reuse it with no code change. Whole-file replacement silently drops the repository's entries under a user's. The labels keep a workaround visibly temporary instead of turning into a permanent, respectable name.

Rejected:

• if title == ... in the core: title knowledge in code.
• Hashing the title directory: tens of gigabytes per run.
• Whole-file override: user settings erase shipped compatibility entries.
• Negative booleans such as disable_x: double negatives once forced on.