refactor: harden internal daemon entrypoint and cleanup observations

Remove the internal daemon subcommand from the public CLI surface,
start the daemon via an internal env trigger, and ensure generated
completions/help never expose internal entrypoints.

Also finish the pending observation cleanups and docs updates,
including config/key deduplication, registry matching cleanup, and
remaining roadmap/project map staleness fixes.

tests/http_api.rs

@@ -14,7 +14,7 @@ use tokio::{net::TcpListener as TokioTcpListener, sync::Mutex, task::JoinHandle,
 use tvctl::{
     adapters::Device,
     daemon::{
-        Daemon, SharedDaemon,
+        Daemon, INTERNAL_DAEMON_ENV, SharedDaemon,
         cache::AppCacheStore,
         config::{DaemonConfig, DevConfig, DiscoveryConfig, RuntimePaths, TvctlConfig},
         discovery::DiscoveryService,
@@ -102,7 +102,7 @@ impl TestDaemon {
 
         let binary = std::env::var("CARGO_BIN_EXE_tvctl").expect("binary path should exist");
         let child = Command::new(binary)
-            .arg("__daemon_serve")
+            .env(INTERNAL_DAEMON_ENV, "1")
             .env("HOME", &home)
             .env("XDG_CONFIG_HOME", &config_home)
             .env("XDG_DATA_HOME", &data_home)