fix(matrix): @mention detection, sync reliability, and duplicate code cleanup

[eldelosdatos]

Summary

• Fix @mention detection for Element/Matrix clients — Element sends mentions as HTML pills in formatted_body and via m.mentions.user_ids[], not in plain text body. The adapter only checked body, making group_policy=mention_only (default) silently drop all messages in group rooms.
• Add HTTP client timeout to prevent sync hangs — reqwest::Client::new() has no timeout. If the homeserver drops TCP silently, /sync hangs forever, killing message reception permanently.
• Remove duplicate mention/DM detection code — FIX not able to run openfang in ubuntu 22.04 #2 and FIX Invalid request for kimi #3 blocks were duplicated, overwriting metadata on the second pass.
• Add heartbeat_interval_secs=300 to assistant agent — Default 30s creates 60s timeout, causing idle agents to crash-loop every 90s.
• Add comprehensive observability logging — Structured logs at every decision point in sync loop, bridge dispatch, and agent routing.
• Add 9 integration tests with wiremock for Matrix adapter.

Problem Details

@mention detection (critical)

// Before: only checks plain text body
if content.contains(&user_id) { ... }

// After: checks body + HTML + m.mentions spec
let mentioned_in_body = content.contains(&user_id);
let mentioned_in_html = event["content"]["formatted_body"]
    .as_str().map(|html| html.contains(&user_id)).unwrap_or(false);
let mentioned_in_m_mentions = event["content"]["m.mentions"]["user_ids"]
    .as_array().map(|ids| ids.iter().any(|id| id.as_str() == Some(&user_id)))
    .unwrap_or(false);

Element sends:

• body: hola (no MXID)
• formatted_body: <a href="https://matrix.to/#/@bot:server">Bot</a> hola
• m.mentions.user_ids: ["@bot:server"]

HTTP timeout

// Before: no timeout — hangs forever on dropped connections
client: reqwest::Client::new(),

// After: 90s total, 30s connect
client: reqwest::Client::builder()
    .timeout(Duration::from_secs(90))
    .connect_timeout(Duration::from_secs(30))
    .build()

Duplicate code

The FIX #2 (mention detection) and FIX #3 (DM detection) blocks were copy-pasted twice in the sync loop. The second copy overwrites metadata from the first, losing the DM detection results.

Test Plan

• cargo check -p openfang-channels — compiles cleanly
• cargo test -p openfang-channels — 12/12 tests pass (9 new + 3 existing)
• Tested on Railway with Synapse homeserver + Element client
• Verified Element @mentions detected via formatted_body and m.mentions
• Verified sync recovery after connection drops
• Verified group_policy=mention_only works correctly with Element pills

New Tests

Test	What it validates
test_adapter_auth_and_start	Auth + sync loop init
test_adapter_auth_failure	401 error handling
test_sync_receives_message	End-to-end message reception
test_sync_skips_own_messages	Self-message filtering
test_sync_retries_on_error	Error retry with backoff
test_shutdown_stops_sync	Clean shutdown via signal
test_command_parsing	/command args parsing
test_dedup_events	Duplicate event filtering
test_allowed_rooms_filter	Room allowlist enforcement

Breaking Changes

None. All changes are backward-compatible.

🤖 Generated with Claude Code

[jaberjaber23]

Thanks for the matrix reliability work @eldelosdatos — the sync retry + @mention detection improvements look solid.

Ship-blocker in the current head: agents/assistant/agent.toml around line 144 has two keys concatenated on one line without a newline separator:

toml [autonomous] heartbeat_interval_secs = 300max_iterations = 100

This is invalid TOML and will break every deployment that uses the bundled assistant agent. Please change it to:

toml [autonomous] heartbeat_interval_secs = 300 max_iterations = 100

Rebase on latest main (post-#1041) at the same time so CI runs. Happy to merge once that's fixed and green.