Remove all alternate update paths — fleet redeploy is release + upgrade all

Killed:
- rebuild_and_restart (in-container cargo self-compile): the MCP tool,
  the `rebuild` chat command in all four transports, the web-ui bot
  command, and the underlying function. This was the path that caused
  the exec() deadlocks.
- upgrade_sled gateway MCP tool: second entry point to sled upgrades,
  defaulted to serving the gateway's own macOS binary to Linux sleds.
- GET /api/huskies-binary (both sled and gateway route trees): served
  current_exe(), wrong platform when the gateway is macOS. Superseded
  by /api/artifacts/ which now also serves on the gateway route tree.
- `huskies upgrade` CLI subcommand and --source flag: third way of
  doing the same download-and-replace. Escape hatch for a bricked sled
  is `docker cp` + restart.

Kept, distinct jobs: `project-rebuild` (container/image updates),
`rebuild gateway` + script/local-release (gateway self-update).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019fHdm92yjvguPi2LiXfLB9

server/src/chat/transport/matrix/rebuild.rs

@@ -1,51 +1,19 @@
-//! Rebuild command: trigger a server rebuild and restart.
+//! `rebuild gateway` command parsing.
 //!
-//! `{bot_name} rebuild` stops all running agents, rebuilds the server binary
-//! with `cargo build`, and re-execs the process with the new binary.  If the
-//! build fails the error is reported back to the room and the server keeps
-//! running.
+//! The old `rebuild` command (in-container cargo build + restart of a sled)
+//! was removed: fleet binary updates go through `release` + `upgrade all`
+//! exclusively.  Only the gateway self-rebuild command remains here.
 
-use crate::agents::AgentPool;
 use crate::chat::util::strip_bot_mention;
-use std::path::Path;
-use std::sync::Arc;
 
 /// A parsed rebuild command.
 #[derive(Debug, PartialEq)]
 pub struct RebuildCommand;
 
-/// Parse a rebuild command from a raw message body.
-///
-/// Strips the bot mention prefix and checks whether the command word is
-/// `rebuild`.  Returns `None` when the message is not a rebuild command.
-pub fn extract_rebuild_command(
-    message: &str,
-    bot_name: &str,
-    bot_user_id: &str,
-) -> Option<RebuildCommand> {
-    let stripped = strip_bot_mention(message, bot_name, bot_user_id);
-    let trimmed = stripped
-        .trim()
-        .trim_start_matches(|c: char| !c.is_alphanumeric());
-
-    let cmd = match trimmed.split_once(char::is_whitespace) {
-        Some((c, _)) => c,
-        None => trimmed,
-    };
-
-    if cmd.eq_ignore_ascii_case("rebuild") {
-        Some(RebuildCommand)
-    } else {
-        None
-    }
-}
-
 /// Parse a "rebuild gateway" command from a raw message body.
 ///
 /// Returns `Some(RebuildCommand)` only when the stripped message begins with
-/// "rebuild gateway" (case-insensitive).  A plain "rebuild" without the
-/// "gateway" qualifier returns `None` so it falls through to the standard
-/// server rebuild handler.
+/// "rebuild gateway" (case-insensitive).
 pub fn extract_rebuild_gateway_command(
     message: &str,
     bot_name: &str,
@@ -77,23 +45,6 @@ pub fn extract_rebuild_gateway_command(
     }
 }
 
-/// Handle a rebuild command: trigger server rebuild and restart.
-///
-/// Returns a string describing the outcome.  On build failure the error
-/// message is returned so it can be posted to the room; the server keeps
-/// running.  On success this function never returns (the process re-execs).
-pub async fn handle_rebuild(
-    bot_name: &str,
-    project_root: &Path,
-    agents: &Arc<AgentPool>,
-) -> String {
-    crate::slog!("[matrix-bot] rebuild command received (bot={bot_name})");
-    match crate::rebuild::rebuild_and_restart(agents, project_root, None).await {
-        Ok(msg) => msg,
-        Err(e) => format!("Rebuild failed: {e}"),
-    }
-}
-
 // ---------------------------------------------------------------------------
 // Tests
 // ---------------------------------------------------------------------------
@@ -103,46 +54,21 @@ mod tests {
     use super::*;
 
     #[test]
-    fn extract_with_display_name() {
-        let cmd = extract_rebuild_command("Timmy rebuild", "Timmy", "@timmy:home.local");
-        assert_eq!(cmd, Some(RebuildCommand));
-    }
-
-    #[test]
-    fn extract_with_full_user_id() {
+    fn extract_gateway_rebuild() {
         let cmd =
-            extract_rebuild_command("@timmy:home.local rebuild", "Timmy", "@timmy:home.local");
+            extract_rebuild_gateway_command("Timmy rebuild gateway", "Timmy", "@timmy:home.local");
         assert_eq!(cmd, Some(RebuildCommand));
     }
 
     #[test]
-    fn extract_with_localpart() {
-        let cmd = extract_rebuild_command("@timmy rebuild", "Timmy", "@timmy:home.local");
-        assert_eq!(cmd, Some(RebuildCommand));
-    }
-
-    #[test]
-    fn extract_case_insensitive() {
-        let cmd = extract_rebuild_command("Timmy REBUILD", "Timmy", "@timmy:home.local");
-        assert_eq!(cmd, Some(RebuildCommand));
-    }
-
-    #[test]
-    fn extract_non_rebuild_returns_none() {
-        let cmd = extract_rebuild_command("Timmy help", "Timmy", "@timmy:home.local");
+    fn plain_rebuild_is_not_gateway_rebuild() {
+        let cmd = extract_rebuild_gateway_command("Timmy rebuild", "Timmy", "@timmy:home.local");
         assert_eq!(cmd, None);
     }
 
     #[test]
-    fn extract_ignores_extra_args() {
-        // "rebuild" with trailing text is still a rebuild command
-        let cmd = extract_rebuild_command("Timmy rebuild now", "Timmy", "@timmy:home.local");
-        assert_eq!(cmd, Some(RebuildCommand));
-    }
-
-    #[test]
-    fn extract_no_match_returns_none() {
-        let cmd = extract_rebuild_command("Timmy status", "Timmy", "@timmy:home.local");
+    fn non_rebuild_returns_none() {
+        let cmd = extract_rebuild_gateway_command("Timmy status", "Timmy", "@timmy:home.local");
         assert_eq!(cmd, None);
     }
 }