One reader (gateway.platforms._shared.extra_or_secret) now implements the
precedence every per-profile setting follows for the OWNING profile:
explicit scoped env/.env → that profile's config.yaml (PlatformConfig.extra)
→ the adapter's default. A scoped miss returns the default, never the launch
process's os.environ; single-profile / default-profile installs keep the
documented env-over-YAML contract.
Why: 545e74d0ea (#108705) stopped bridging a secondary's YAML into the
process env and moved readers to config.extra, but the shared reader and the
hand-rolled helpers in Discord/Slack/Matrix/Telegram consulted YAML FIRST and
then fell back to a scoped env read. Two bug classes followed (#108440
post-merge review by andrexibiza, #109032):
- an explicit env value could no longer beat YAML for the owning profile
(DISCORD_ALLOW_MENTION_EVERYONE=false lost to allow_mentions.everyone: true;
TELEGRAM_REACTIONS=true lost to the stock reactions: false);
- a secondary that OMITTED a key inherited the launch profile's bridged env
through the fallback (Matrix process_notices/session_scope, Discord
auto_thread/reactions/mentions, Slack reactions/ignored_channels).
Consumers migrated to the shared reader: Discord _build_allowed_mentions and
_extra_or_env_flag; Slack _slack_allow_bots, _reactions_enabled (the
_extra_or_env_* getters already used it); Matrix _extra_truthy, _extra_csv_set,
session_scope, reactions, require_mention parsers, and — new — the
allowed_users / ignore_user_patterns consumers that never read the seeded YAML
lists; Telegram _extra_bool, _extra_str_set, _reactions_enabled; Feishu
allow_bots; WhatsApp dm_policy/group_policy.
Refs #108440, #109032
3dedb71f2f