Rename the project to Echo (was fedserv)

Rebrand the daemon and workspace: the binary is now `echo`, every crate
is `echo-*` (`echo-api` and the module crates), Rust imports use
`echo_*`, the gRPC proto is `proto/echo.proto` with package `echo.v1`,
and the log filter, gossip peer-name default, and on-disk store default
(`echo.db.jsonl`) follow. Docs updated throughout. No behaviour change;
crate directories and the config schema are untouched.

modules/chanfix/Cargo.toml

@@ -1,8 +1,8 @@
 [package]
-name = "fedserv-chanfix"
+name = "echo-chanfix"
 version = "0.0.1"
 edition = "2021"
 description = "ChanFix: reop opless unregistered channels from accumulated op-time scores."
 
 [dependencies]
-fedserv-api = { path = "../../api" }
+echo-api = { path = "../../api" }

modules/chanfix/src/fix.rs

@@ -1,4 +1,4 @@
-use fedserv_api::{NetView, Sender, ServiceCtx, Store};
+use echo_api::{NetView, Sender, ServiceCtx, Store};
 
 // A channel with this many ops isn't opless and needs no fix.
 const OP_THRESHOLD: usize = 3;

modules/chanfix/src/lib.rs

@@ -6,7 +6,7 @@
 //! SCORES <#channel> shows the standings; CHANFIX <#channel> performs the fix.
 //! `lib.rs` holds the dispatcher; each command lives in its own file.
 
-use fedserv_api::{NetView, Sender, Service, ServiceCtx, Store};
+use echo_api::{NetView, Sender, Service, ServiceCtx, Store};
 
 #[path = "scores.rs"]
 mod scores;

modules/chanfix/src/scores.rs

@@ -1,4 +1,4 @@
-use fedserv_api::{NetView, Sender, ServiceCtx};
+use echo_api::{NetView, Sender, ServiceCtx};
 
 // SCORES <#channel>: show the op-time standings ChanFix would reop from.
 pub fn handle(me: &str, from: &Sender, chan: Option<&str>, ctx: &mut ServiceCtx, net: &dyn NetView) {