refactor(web): remove --dev; mount the reload chain unconditionally

The client-hmr row joins the web bundle as an ordinary always-on roster
row: without a rebuild watcher rewriting client bundles it polls
unchanged files and stays idle. This deletes the --dev flag, the web
runtime's mode config, the mode-forked prompt contract, the DSH_WEB_MODE
bash variable, and the post-settlement row-creation machinery the
conditional row required. dsh web + pnpm run dev:web remains the
development loop.

packages/bundle/web-app/src/startup.ts

@@ -1,6 +1,6 @@
 /**
  * The web app's command-line provider: it parses the `dsh --profile web` flag
- * family (`--host`, `--port`, `--dev`, `--trusted-host`) and its `--help`
+ * family (`--host`, `--port`, `--trusted-host`) and its `--help`
  * text, then provides the immutable values as {@link WEB_STARTUP_SERVICE}.
  * Ordinary rows inject that service before reading it from lazy config.
  * @module @deepseek-ai/dsh-web-app/startup
@@ -25,8 +25,6 @@ export interface WebStartupValues {
   host?: string
   /** `--port`, absent when the invocation did not name one. */
   port?: number
-  /** Web runtime mode; `--dev` selects development, which also mounts the client-plugin reload chain. */
-  mode: 'production' | 'development'
   /** Explicit `--trusted-host` authorities, in argument order. */
   trustedHosts: string[]
 }
@@ -35,7 +33,6 @@ export interface WebStartupValues {
 interface WebOptions {
   host?: string
   port?: string
-  dev?: boolean
   trustedHost?: string[]
 }
 
@@ -50,14 +47,12 @@ function webCommand(): Command {
     .helpOption('-h, --help', 'show this help')
     .option('--host <host>', 'bind host; pass 0.0.0.0 to reach it from another machine')
     .option('--port <port>', 'listen port; pass 0 to let the OS pick a free one')
-    .option('--dev', 'mount the client-plugin HMR receiver (run pnpm run dev:web separately to rebuild bundles)')
     .option('--trusted-host <authority...>', 'extra authority the /api browser-trust fence accepts (host or host:port; repeatable)')
     .addHelpText('after', `
 Examples:
   dsh --profile web                          serve on the composed host and port
   dsh --profile web --port 8080              serve on another port
   dsh --profile web --host 0.0.0.0           reach it from another machine on the LAN
-  dsh --profile web --dev                    mount the client-plugin HMR receiver
 `)
 }
 
@@ -74,7 +69,6 @@ function planWebStartup(program: Command): WebStartupValues {
   return {
     ...options.host !== undefined && { host: options.host },
     ...options.port !== undefined && { port: Number(options.port) },
-    mode: options.dev === true ? 'development' : 'production',
     trustedHosts: options.trustedHost ?? [],
   }
 }