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 Superseded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/http/mcp/diagnostics/mod.rs

@@ -3,7 +3,6 @@
 use crate::agents::move_story_to_stage;
 use crate::http::context::AppContext;
 use crate::log_buffer;
-use crate::slog;
 use serde_json::{Value, json};
 
 mod permission;
@@ -43,23 +42,6 @@ pub(crate) fn tool_get_server_logs(args: &Value) -> Result<String, String> {
     Ok(all_lines[start..].join("\n"))
 }
 
-/// Rebuild the server binary and re-exec (delegates to `crate::rebuild`).
-pub(crate) async fn tool_rebuild_and_restart(ctx: &AppContext) -> Result<String, String> {
-    slog!("[rebuild] Rebuild and restart requested via MCP tool");
-
-    // Signal the Matrix bot (if active) so it can send its own shutdown
-    // announcement before the process is replaced.  Best-effort: we wait up
-    // to 1.5 s for the message to be delivered.
-    if let Some(ref tx) = ctx.matrix_shutdown_tx {
-        let _ = tx.send(Some(crate::rebuild::ShutdownReason::Rebuild));
-        tokio::time::sleep(std::time::Duration::from_millis(1500)).await;
-    }
-
-    let project_root = ctx.state.get_project_root().unwrap_or_default();
-    let notifier = ctx.bot_shutdown.as_deref();
-    crate::rebuild::rebuild_and_restart(&ctx.services.agents, &project_root, notifier).await
-}
-
 /// MCP tool called by Claude Code via `--permission-prompt-tool`.
 ///
 /// Forwards the permission request through the shared channel to the active

server/src/http/mcp/diagnostics/permission.rs

@@ -335,57 +335,6 @@ mod tests {
         assert_eq!(servers[0], "huskies");
     }
 
-    #[test]
-    fn rebuild_and_restart_in_tools_list() {
-        use super::super::super::tools_list::handle_tools_list;
-        let resp = handle_tools_list(Some(json!(1)));
-        let tools = resp.result.unwrap()["tools"].as_array().unwrap().clone();
-        let tool = tools.iter().find(|t| t["name"] == "rebuild_and_restart");
-        assert!(
-            tool.is_some(),
-            "rebuild_and_restart missing from tools list"
-        );
-        let t = tool.unwrap();
-        assert!(t["description"].as_str().unwrap().contains("Rebuild"));
-        assert!(t["inputSchema"].is_object());
-    }
-
-    #[tokio::test]
-    async fn rebuild_and_restart_kills_agents_before_build() {
-        // Verify that calling rebuild_and_restart on an empty pool doesn't
-        // panic and proceeds to the build step. We can't test exec() in a
-        // unit test, but we can verify the build attempt happens.
-        let tmp = tempfile::tempdir().unwrap();
-        let ctx = test_ctx(tmp.path());
-
-        // The build will succeed (we're running in the real workspace) and
-        // then exec() will be called — which would replace our test process.
-        // So we only test that the function *runs* without panicking up to
-        // the agent-kill step. We do this by checking the pool is empty.
-        assert_eq!(ctx.services.agents.list_agents().await.unwrap().len(), 0);
-        ctx.services.agents.kill_all_children().await; // should not panic on empty pool
-    }
-
-    #[test]
-    fn rebuild_uses_matching_build_profile() {
-        // The build must use the same profile (debug/release) as the running
-        // binary, otherwise cargo build outputs to a different target dir and
-        // current_exe() still points at the old binary.
-        let build_args: Vec<&str> = if cfg!(debug_assertions) {
-            vec!["build", "-p", "huskies"]
-        } else {
-            vec!["build", "--release", "-p", "huskies"]
-        };
-
-        // Tests always run in debug mode, so --release must NOT be present.
-        assert!(
-            !build_args.contains(&"--release"),
-            "In debug builds, rebuild must not pass --release (would put \
-             the binary in target/release/ while current_exe() points to \
-             target/debug/)"
-        );
-    }
-
     // ── move_story tool tests ─────────────────────────────────────
 
     #[test]

server/src/http/mcp/dispatch.rs

@@ -81,8 +81,6 @@ pub async fn dispatch_tool_call(
         // Diagnostics
         "get_server_logs" => diagnostics::tool_get_server_logs(&args),
         "get_version" => diagnostics::tool_get_version(ctx),
-        // Server lifecycle
-        "rebuild_and_restart" => diagnostics::tool_rebuild_and_restart(ctx).await,
         // Permission bridge (Claude Code → frontend dialog)
         "prompt_permission" => diagnostics::tool_prompt_permission(&args, ctx).await,
         // Token usage

server/src/http/mcp/tools_list/mod.rs

@@ -78,7 +78,6 @@ mod tests {
         assert!(names.contains(&"get_server_logs"));
         assert!(names.contains(&"prompt_permission"));
         assert!(names.contains(&"get_pipeline_status"));
-        assert!(names.contains(&"rebuild_and_restart"));
         assert!(names.contains(&"get_token_usage"));
         assert!(names.contains(&"move_story"));
         assert!(names.contains(&"unblock_story"));
@@ -117,7 +116,7 @@ mod tests {
         assert!(names.contains(&"convert_item_type"));
         assert!(names.contains(&"edit"));
         assert!(names.contains(&"write"));
-        assert_eq!(tools.len(), 85);
+        assert_eq!(tools.len(), 84);
     }
 
     #[test]

server/src/http/mcp/tools_list/system_tools.rs

@@ -42,14 +42,6 @@ pub(super) fn system_tools() -> Vec<Value> {
                 "properties": {}
             }
         }),
-        json!({
-            "name": "rebuild_and_restart",
-            "description": "Rebuild the server binary from source and re-exec with the new binary. Gracefully stops all running agents before restart. If the build fails, the server stays up and returns the build error.",
-            "inputSchema": {
-                "type": "object",
-                "properties": {}
-            }
-        }),
         json!({
             "name": "prompt_permission",
             "description": "Present a permission request to the user via the web UI. Used by Claude Code's --permission-prompt-tool to delegate permission decisions to the frontend dialog. Returns on approval; returns an error on denial.",