feat(channels): enhance Discord with mention-only mode, thread routing, and typing indicators (#2842)

* feat(channels): enhance Discord with mention-only mode, thread routing, and typing indicators

Add mention_only config to only respond when bot is mentioned, with
allowed_channels override. Add thread_mode for Hermes-style auto-thread
creation. Add periodic typing indicators while bot is processing.

* fix(discord): include allowed_channels in mention_only skip condition (line 274)

* docs: fix Discord config example to match boolean thread_mode implementation

* style: format with ruff

* fix(discord): apply Copilot review fixes and resolve lint errors

- Remove unused Optional import
- Fix thread_ts type hints to str | None
- Fix has_mention logic for None values
- Implement thread_mode fallback to channel replies on thread creation failure
- Fix thread_mode docstring alignment
- Fix allowed_channels comment formatting in config.example.yaml

* fix(discord): reset context for orphaned threads in mention_only mode

When a message arrives in a thread not tracked by _active_threads,
clear thread_id and typing_target so the message falls through to
the standard channel handling pipeline, which creates a fresh thread
instead of incorrectly routing to the stale thread.

* fix(discord): create new thread on @ when channel has existing tracked thread

When mention_only is enabled and a user @-s the bot in a channel
that already has a tracked thread, create a new thread instead of
incorrectly routing to the old one.

* fix(discord): allow no-@ thread replies while skipping no-@ channel messages

The skip block for no-@ messages was too aggressive — it blocked
continuation replies within tracked threads AND incorrectly routed
no-@ channel messages to the existing thread.

Now:
- Thread message, no @ → routed to existing tracked thread
- Channel message, no @ → skipped
- Channel message, with @ → creates new thread

* feat(discord): add checkmark reaction to acknowledge received messages

* Move discord.py to optional dependency and auto-detect from config.yaml

- Add discord extra to [project.optional-dependencies] in pyproject.toml
- Update detect_uv_extras.py to map channels.discord.enabled: true -> --extra discord
- Set UV_EXTRAS=discord in docker-compose-dev.yaml gateway env

* fix(discord): persist thread-channel mappings to store for recovery after restart

Discord's _active_threads dict was purely in-memory, so all channel-to-thread
mappings were lost on server restart. This fix bridges ChannelStore into
DiscordChannel:

- Save thread mappings to store.json after every thread creation
- Restore active threads from store on DiscordChannel startup
- Pass channel_store to all channels via service.py config injection

Store keys follow the pattern: discord:<channel_id>:<thread_id>

* fix(discord): address Copilot review — fix types, typing targets, cross-thread safety, and config comments

* fix(tests): add multitask_strategy param to mock for clarification follow-up test

* fix(tests): explicitly set model_name=None for title middleware test isolation

* fix(discord): use trigger_typing() instead of typing() for typing indicators

discord.py 2.x TextChannel.typing() and Thread.typing() are async context
managers, not one-shot coroutines. Use trigger_typing() for periodic
typing indicator pings.

* fix(discord): cancel typing tasks on channel shutdown

Prevents 'Task was destroyed but it is pending' warnings when the
Discord client stops while typing indicator loops are still running.

* fix(scripts): detect nested YAML config for discord extra

section_value() only matched top-level YAML sections. Added
nested_section_value() that handles two-level nesting (e.g.,
channels.discord.enabled), so auto-detection of the discord
extra works when config uses the standard nested format.

* fix(docker): remove hard-coded UV_EXTRAS=discord from dev compose

Relies on auto-detection via detect_uv_extras.py instead of forcing
discord.py install even when channels.discord.enabled is false.
Matches production docker-compose.yaml behavior (UV_EXTRAS:-).

* refactor(nginx): move proxy_buffering/proxy_cache to server level

DRY cleanup — these directives were repeated in 14 location blocks.
Set at server level once, reducing duplication and risk of drift.

* fix(discord): use dedicated JSON file for thread persistence

Replace ChannelStore usage for Discord thread-ID persistence with a
dedicated discord_threads.json file. ChannelStore is designed to map
IM conversations to DeerFlow thread IDs — using it to persist Discord
thread IDs was semantically wrong and confusing.

Changes:
- _save_thread() now reads/writes a simple {channel_id: thread_id} JSON dict
- _load_active_threads() reads directly from the JSON file
- File path derived from ChannelStore directory (when available) or
  defaults to ~/.deer-flow/channels/discord_threads.json
- Removed unused ChannelStore import

* fix(discord): address WillemJiang's code review comments on PR #2842

1. Remove semantically incorrect message_in_thread variable. At this code
   point (after the Thread case is handled above), we're guaranteed to be in
   a channel, not a thread. Always apply mention_only check here.

2. Add _active_thread_ids reverse-lookup set for O(1) thread ID membership
   checks instead of O(n) scan of _active_threads.values(). Keep the set
   in sync with _active_threads in _load_active_threads() and _save_thread().

3. Add _thread_store_lock (threading.Lock) to protect _active_threads and
   the JSON file from concurrent access between the Discord loop thread
   (_run_client) and the main thread (_load_active_threads, _save_thread).

docker/nginx/nginx.conf

@@ -28,6 +28,10 @@ http {
         set $gateway_upstream gateway:8001;
         set $frontend_upstream frontend:3000;
 
+        # Default proxy settings for all locations (streaming/SSE support)
+        proxy_buffering off;
+        proxy_cache off;
+
         # Keep the unified nginx endpoint same-origin by default. When split
         # frontend/backend or port-forwarded deployments need browser CORS,
         # configure the Gateway allowlist with GATEWAY_CORS_ORIGINS so CORS and
@@ -49,8 +53,6 @@ http {
             proxy_set_header Connection '';
 
             # SSE/Streaming support
-            proxy_buffering off;
-            proxy_cache off;
             proxy_set_header X-Accel-Buffering no;
 
             # Timeouts for long-running requests
@@ -70,6 +72,7 @@ http {
             proxy_set_header X-Real-IP $remote_addr;
             proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
             proxy_set_header X-Forwarded-Proto $scheme;
+
         }
 
         # Custom API: Memory endpoint
@@ -80,6 +83,7 @@ http {
             proxy_set_header X-Real-IP $remote_addr;
             proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
             proxy_set_header X-Forwarded-Proto $scheme;
+
         }
 
         # Custom API: MCP configuration endpoint
@@ -90,6 +94,7 @@ http {
             proxy_set_header X-Real-IP $remote_addr;
             proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
             proxy_set_header X-Forwarded-Proto $scheme;
+
         }
 
         # Custom API: Skills configuration endpoint
@@ -100,6 +105,7 @@ http {
             proxy_set_header X-Real-IP $remote_addr;
             proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
             proxy_set_header X-Forwarded-Proto $scheme;
+
         }
 
         # Custom API: Agents endpoint
@@ -110,6 +116,7 @@ http {
             proxy_set_header X-Real-IP $remote_addr;
             proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
             proxy_set_header X-Forwarded-Proto $scheme;
+
         }
 
         # Custom API: Uploads endpoint
@@ -124,6 +131,8 @@ http {
             # Large file upload support
             client_max_body_size 100M;
             proxy_request_buffering off;
+
+            # Disable response buffering to avoid permission errors
         }
 
         # Custom API: Other endpoints under /api/threads
@@ -134,6 +143,7 @@ http {
             proxy_set_header X-Real-IP $remote_addr;
             proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
             proxy_set_header X-Forwarded-Proto $scheme;
+
         }
 
         # API Documentation: Swagger UI
@@ -144,6 +154,7 @@ http {
             proxy_set_header X-Real-IP $remote_addr;
             proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
             proxy_set_header X-Forwarded-Proto $scheme;
+
         }
 
         # API Documentation: ReDoc
@@ -154,6 +165,7 @@ http {
             proxy_set_header X-Real-IP $remote_addr;
             proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
             proxy_set_header X-Forwarded-Proto $scheme;
+
         }
 
         # API Documentation: OpenAPI Schema
@@ -164,6 +176,7 @@ http {
             proxy_set_header X-Real-IP $remote_addr;
             proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
             proxy_set_header X-Forwarded-Proto $scheme;
+
         }
 
         # Health check endpoint (gateway)
@@ -174,6 +187,7 @@ http {
             proxy_set_header X-Real-IP $remote_addr;
             proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
             proxy_set_header X-Forwarded-Proto $scheme;
+
         }
 
         # ── Provisioner API (sandbox management) ────────────────────────
@@ -187,6 +201,7 @@ http {
             proxy_set_header X-Real-IP $remote_addr;
             proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
             proxy_set_header X-Forwarded-Proto $scheme;
+
         }
 
         # Catch-all for /api/ routes not covered above (e.g. /api/v1/auth/*).
@@ -198,6 +213,9 @@ http {
             proxy_set_header X-Real-IP $remote_addr;
             proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
             proxy_set_header X-Forwarded-Proto $scheme;
+
+            # Disable buffering to avoid permission errors when nginx
+            # runs as a non-root user (e.g. local development).
         }
 
         # All other requests go to frontend
@@ -220,4 +238,4 @@ http {
             proxy_read_timeout 600s;
         }
     }
-}
+}

docker/nginx/nginx.local.conf

@@ -70,6 +70,11 @@ http {
             proxy_set_header X-Real-IP $remote_addr;
             proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
             proxy_set_header X-Forwarded-Proto $scheme;
+
+            # Disable buffering to avoid permission errors when nginx
+            # runs as a non-root user (e.g. local development).
+            proxy_buffering off;
+            proxy_cache off;
         }
 
         # Custom API: Memory endpoint
@@ -80,6 +85,9 @@ http {
             proxy_set_header X-Real-IP $remote_addr;
             proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
             proxy_set_header X-Forwarded-Proto $scheme;
+
+            proxy_buffering off;
+            proxy_cache off;
         }
 
         # Custom API: MCP configuration endpoint
@@ -90,6 +98,9 @@ http {
             proxy_set_header X-Real-IP $remote_addr;
             proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
             proxy_set_header X-Forwarded-Proto $scheme;
+
+            proxy_buffering off;
+            proxy_cache off;
         }
 
         # Custom API: Skills configuration endpoint
@@ -100,6 +111,9 @@ http {
             proxy_set_header X-Real-IP $remote_addr;
             proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
             proxy_set_header X-Forwarded-Proto $scheme;
+
+            proxy_buffering off;
+            proxy_cache off;
         }
 
         # Custom API: Agents endpoint
@@ -110,6 +124,9 @@ http {
             proxy_set_header X-Real-IP $remote_addr;
             proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
             proxy_set_header X-Forwarded-Proto $scheme;
+
+            proxy_buffering off;
+            proxy_cache off;
         }
 
         # Custom API: Uploads endpoint
@@ -124,6 +141,10 @@ http {
             # Large file upload support
             client_max_body_size 100M;
             proxy_request_buffering off;
+
+            # Disable response buffering to avoid permission errors
+            proxy_buffering off;
+            proxy_cache off;
         }
 
         # Custom API: Other endpoints under /api/threads
@@ -134,6 +155,9 @@ http {
             proxy_set_header X-Real-IP $remote_addr;
             proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
             proxy_set_header X-Forwarded-Proto $scheme;
+
+            proxy_buffering off;
+            proxy_cache off;
         }
 
         # API Documentation: Swagger UI
@@ -144,6 +168,9 @@ http {
             proxy_set_header X-Real-IP $remote_addr;
             proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
             proxy_set_header X-Forwarded-Proto $scheme;
+
+            proxy_buffering off;
+            proxy_cache off;
         }
 
         # API Documentation: ReDoc
@@ -154,6 +181,9 @@ http {
             proxy_set_header X-Real-IP $remote_addr;
             proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
             proxy_set_header X-Forwarded-Proto $scheme;
+
+            proxy_buffering off;
+            proxy_cache off;
         }
 
         # API Documentation: OpenAPI Schema
@@ -164,6 +194,9 @@ http {
             proxy_set_header X-Real-IP $remote_addr;
             proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
             proxy_set_header X-Forwarded-Proto $scheme;
+
+            proxy_buffering off;
+            proxy_cache off;
         }
 
         # Health check endpoint (gateway)
@@ -174,6 +207,9 @@ http {
             proxy_set_header X-Real-IP $remote_addr;
             proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
             proxy_set_header X-Forwarded-Proto $scheme;
+
+            proxy_buffering off;
+            proxy_cache off;
         }
 
         # Catch-all for any /api/* prefix not matched by a more specific block above.
@@ -193,6 +229,11 @@ http {
             # Auth endpoints set HttpOnly cookies — make sure nginx doesn't
             # strip the Set-Cookie header from upstream responses.
             proxy_pass_header Set-Cookie;
+
+            # Disable buffering to avoid permission errors when nginx
+            # runs as a non-root user (e.g. local development).
+            proxy_buffering off;
+            proxy_cache off;
         }
 
         # All other requests go to frontend