feat(slack): per-message acknowledgment reactions, phases, reconnect supervision, and Block Kit

Cargo.toml

@@ -308,7 +308,9 @@ tower       = "0.5"
 tower-http  = "0.6"
 url         = "2"
 urlencoding = "2"
-web-push    = "0.11"
+# Form bodies (application/x-www-form-urlencoded)
+form_urlencoded = "1"
+web-push        = "0.11"
 # Metrics
 metrics                     = "0.24"
 metrics-exporter-prometheus = "0.16"

crates/channels/Cargo.toml

@@ -15,6 +15,7 @@ serde          = { workspace = true }
 serde_json     = { workspace = true }
 thiserror      = { workspace = true }
 tokio          = { workspace = true }
+tokio-util     = { workspace = true }
 tracing        = { workspace = true }
 url            = { workspace = true }
 

crates/channels/src/activity.rs

@@ -0,0 +1,68 @@
+//! Channel acknowledgment-reaction signals.
+//!
+//! Small value types shared across the chat layer (which emits them) and the
+//! gateway (which forwards them to a per-session reaction controller). Kept in
+//! their own module so the plugin module stays focused.
+
+/// Canonical acknowledgment-reaction emoji, as Unicode glyphs.
+///
+/// These are the platform-neutral names the reaction controller emits. Each
+/// channel adapts them at its own boundary: Slack normalizes glyphs to
+/// shortcodes (its Web API rejects raw glyphs), while Matrix uses the glyph
+/// itself as the reaction key. Keeping the vocabulary here — rather than
+/// hardcoding one platform's spelling in the controller — is what lets the
+/// controller stay channel-agnostic.
+pub mod ack_emoji {
+    /// Message received, work starting.
+    pub const RECEIVED: &str = "👀";
+    /// Turn completed successfully.
+    pub const SUCCESS: &str = "✅";
+    /// Turn failed.
+    pub const ERROR: &str = "❌";
+    /// Turn is taking a while with no activity.
+    pub const STALL: &str = "⏳";
+    /// Phase: web search / fetch / browsing.
+    pub const WEB: &str = "🌐";
+    /// Phase: shell / process execution.
+    pub const SHELL: &str = "💻";
+    /// Phase: editing or writing files.
+    pub const EDIT: &str = "✏️";
+    /// Phase: deploying / releasing.
+    pub const DEPLOY: &str = "🛫";
+    /// Phase: building / compiling.
+    pub const BUILD: &str = "🏗️";
+    /// Phase: any other tool.
+    pub const TOOL: &str = "🛠️";
+
+    /// Every canonical emoji, for exhaustive per-channel mapping tests.
+    pub const ALL: &[&str] = &[
+        RECEIVED, SUCCESS, ERROR, STALL, WEB, SHELL, EDIT, DEPLOY, BUILD, TOOL,
+    ];
+}
+
+/// Terminal outcome of a channel-dispatched agent turn, used to finalize
+/// acknowledgment reactions (✅ / ❌ / none).
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum ChannelAckOutcome {
+    /// The reply was delivered successfully.
+    Success,
+    /// The turn errored (timeout, provider failure, etc.).
+    Failure,
+    /// The turn was cancelled/aborted — leave no terminal marker.
+    Cancelled,
+}
+
+/// A mid-turn activity signal emitted by the agent run, used to drive channel
+/// acknowledgment reactions (phase emojis) and, later, live status text.
+///
+/// Kept intentionally small — richer phases are derived from the tool name at
+/// the controller.
+#[derive(Debug, Clone)]
+pub enum ChannelActivity {
+    /// The model is reasoning/planning before or between tool calls.
+    Thinking,
+    /// A tool call started; carries the tool name for phase classification.
+    Tool(String),
+    /// The turn finished with the given terminal outcome.
+    Finished(ChannelAckOutcome),
+}