Salvage of PR #41284 onto current main. Relocates the last 9 inline messaging
adapters (+ satellites: telegram_network, feishu_comment/_rules/meeting_invite,
wecom_crypto, wecom_callback) from gateway/platforms/ into self-contained
bundled plugins under plugins/platforms/<x>/, discovered via the platform
registry. Strips the per-platform core touchpoints from gateway/run.py,
gateway/config.py, hermes_cli/gateway.py, hermes_cli/setup.py, and
tools/send_message_tool.py.
Carries forward the migration fixes (explicit enabled:false honored,
get_connected_platforms forces discovery, plugin is_connected via
gateway.get_env_value, logs --component gateway matches plugins.platforms.*,
matrix hidden on Windows).
Additionally ports config keys main added since the PR base: the matrix
plugin's _apply_yaml_config now also covers allowed_users,
ignore_user_patterns, process_notices, and session_scope (the inline
gateway/config.py matrix block gained these in the 1340 commits the PR sat
open; they would otherwise have been silently dropped on deletion).
Convert the salvaged text-debounce delays from HERMES_* env vars to
config.yaml (gateway.platforms.<name>.extra.text_batch_delay_seconds /
text_batch_split_delay_seconds), per the '.env is for secrets only'
policy. Adds a finite/non-negative guard so bad YAML values fall back to
the defaults instead of crashing asyncio.sleep().
- whatsapp.py / weixin.py: read delays via _coerce_float_extra(config.extra)
- update Weixin content-dedup regression test for the deferred dispatch path
- add text-debounce coverage (whatsapp + weixin): defaults, config override,
bad-value fallback, env-var-ignored, burst-collapse, lone-message
- docs: WhatsApp + Weixin config keys
