security: should [lifecycle] and [dream] be read from a project-local uteke.toml? #1534

Problem

.uteke/uteke.toml in a working copy can be an untrusted clone. config_layers::UNTRUSTED_PROJECT_KEYS already strips credentials, endpoints, the embedding backend, [server] and (since #1508) [privacy]. [recall], [tier], [dream] and [lifecycle] are not stripped, and docs/configuration.md says they may be set per project. The CLI and uteke-serve honour them; uteke-mcp will too once #1515 part 4 lands (agents run it inside arbitrary checkouts).

A cloned repository can therefore set [recall] min_score = 1.0 (every recall returns nothing) or destructive thresholds in [lifecycle] (deprecated_ttl_days = 0, max_deprecate_percent = 100, auto_prune_enabled = true, soft_delete_only = false) that the next lifecycle cycle applies to the user's store.

Options

1. Keep as is (per-project lifecycle is a documented feature).
2. Make [lifecycle] and [dream] global-only (add them to the untrusted keys, like [privacy]); [recall] and [tier] stay per project.
3. Also make [recall] global-only.

Notes

Found by the local Cora review of #1515 part 4. A change to the untrusted list is a behaviour change for people who set lifecycle per project; UTEKE_TRUST_PROJECT_CONFIG=1 keeps the old behaviour.