fix(matrix): route text-only send_message through adapter for E2EE support

[hashbender]

Summary

Text-only Matrix messages sent via the send_message engine (hermes send, cron deliver: matrix) now arrive encrypted in E2EE rooms instead of cleartext (red padlock).

Root cause: media sends already routed through the mautrix adapter (_send_matrix_via_adapter), which encrypts. Text-only sends took the raw-HTTP standalone_sender_fn path, which never encrypts — so text landed unencrypted in E2EE rooms.

Changes

• tools/send_message_tool.py: route all Matrix sends through _send_matrix_via_adapter (drop the and media_files gate); remove the now-dead _registry_standalone_send("matrix", ...) branch from the text-only loop. The adapter reuses the live gateway's E2EE session when available ([Bug]: send_message Matrix (media) path reconnects + re-inits E2EE per message — exhausts recipient one-time keys and silently drops messages under burst NousResearch/hermes-agent#46310) and falls back to an encryption-aware ephemeral adapter for standalone/cron.
• tests/tools/test_send_message_tool.py: invert test_matrix_text_only_* to assert the adapter path (was asserting the raw-HTTP path — the bug).

The plugin's standalone_sender_fn stays registered for the registry contract; it is simply no longer reached for Matrix.

Validation

	Before	After
Text-only send in E2EE room	raw HTTP m.text → cleartext (red padlock)	mautrix adapter → encrypted
Media send in E2EE room	adapter → encrypted	adapter → encrypted (unchanged)
Targeted tests	—	169/169 pass
E2E routing check	text → standalone raw-HTTP	text → _send_matrix_via_adapter, raw-HTTP bypassed

Salvaged from NousResearch#20259 (@DanAsBjorn, first submitter) onto current main. The original patched the pre-NousResearch#41112 _send_matrix branch, which had since moved to the plugin's standalone path — same fix direction, re-applied to the current structure. Duplicate NousResearch#23382 (@32r4) fixed the same routing layer with an encryption-flag gate; the unconditional route is simpler and correct since the adapter sends plaintext to unencrypted rooms fine.

Infographic

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Mirror-of: NousResearch#56106
NousResearch#56106

[tenki-reviewer]

Review Complete
No issues found!

Risk: 🟢 Low (12/100) — no findings · 33 LOC across 2 files

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Routes all Matrix sends through the E2EE-capable adapter instead of the raw-HTTP standalone path, fixing cleartext text-only messages that showed a red padlock in encrypted rooms.

Files Reviewed (2 files)

tests/tools/test_send_message_tool.py
tools/send_message_tool.py