Merge origin/main: reconcile Act One integration test (ROADMAP #11) master
Another commit landed on origin/main mid-review: tests/act_one.rs (a new headless integration test) plus a devlog entry, both forked before this branch's stage 4 (devlogs -> wiki/log/) had merged. Git's own rename- directory heuristic correctly proposed moving the new devlog file to wiki/log/2026-07-07-act-one-integration-test.md; accepted and tagged Type: log for consistency with the rest of the tree. One conflict, same shape as the previous merge: wiki/log/DEVLOG.md, both sides inserting a ledger entry at the same splice point. Resolved by union — kept both entries, also fixed the incoming entry's own devlogs/... path mention (now stale post-move) to wiki/log/.... Notable: that commit's own devlog entry independently flags the exact ldconfig/macOS bug fixed in the previous merge commit ("check.sh's pkg-config shim aborts at ldconfig; pre-existing, worked around ... left for a tick") — corroborating it was a real, already-felt problem, not a hypothetical. ./tools/check.sh full green post-merge (96 tests including the new integration suite, both clippy feature sets, bevy build, spec headers, wiki gate, mdbook build, agent-mode smoke).