9d7de6c140
Review findings on d8c467f223, each reproduced through its production path. Stale launch key. `strip_launch_profile_env` built its residue set from a re-parse of the launch `.env`. A key removed or renamed in that file after boot is still in `os.environ` with the old value (dotenv never unsets), and the current file no longer names it, so it survived into the routed child. `_load_dotenv_with_fallback` — the one chokepoint every dotenv load goes through — now records the KEY names it put into the process env, additive for the process lifetime (`launch_dotenv_keys()`), and the strip unions that record with the current file. Source name that lost to the process env. `_apply_external_secret_sources` snapshots every name a source SUPPLIED (`provenance` + `skipped_existing`), but `secret_source_names()` only exposed `_SECRET_SOURCES`, which is provenance metadata and names applied values alone. A launch-profile source that supplied `CUSTOM_VAULT_SECRET` while the process already had it was therefore invisible to the scrub, and a routed child with an empty scope got the launch value. Supplied names are tracked separately (`_SOURCE_SUPPLIED_NAMES`) so the provenance labels stay honest, and `secret_source_names()` returns the union. Last plugin source removed. `_refresh_secret_sources_after_discovery` returned before the cache reset and the installed-scope refresh whenever no plugin source was enabled — and `discover_and_load(force=True)` unloads the old registration first, so removing the final plugin source hit exactly that return with the removed plugin's names still in the per-home snapshot and the current scope. The manager now remembers that a discovery re-applied plugin sources and, on the next discovery that finds none, reconciles once. A home that never had a plugin source is still a no-op (pinned by the existing tests). Regressions: the stale-key lifecycle and the skipped-existing case through `_run_job_script` against a real routed child, and the removal case through the manager. Each checked by reverting its fix and confirming the test fails. (cherry picked from commit d464f5f6126a394cfb47937f683d3a5e2f141840)