refactor(commands): decouple command paths from binary name; drop path presets

Commands no longer hardcode "bl" or their path — the runtime renders the
`<bin> <path>` prefix from each product's registry key, so shared commands
show `bl knowledge retrieve` / `rag retrieve` from one codebase. commands
package now exports only individual commands (no groups/catalog); bl and rag
each spell out their own path map. Also removes the unused export-schema command.

packages/runtime/src/index.ts

@@ -22,7 +22,13 @@ export { BAILIAN_CONSOLE_ROOT, BAILIAN_CONSOLE, API_KEY_PAGE } from "./urls.ts";
 
 // Output facilities consumed by commands
 export { emitResult, emitBare } from "./output/output.ts";
-export { promptText, promptSelect, promptConfirm, failIfMissing } from "./output/prompt.ts";
+export {
+  promptText,
+  promptSelect,
+  promptConfirm,
+  failIfMissing,
+  cmdUsage,
+} from "./output/prompt.ts";
 export { createSpinner, createProgressBar } from "./output/progress.ts";
 export { printWelcomeBanner, printQuickStart } from "./output/banner.ts";
 export { maybeShowStatusBar } from "./output/status-bar.ts";

packages/runtime/src/output/prompt.ts

@@ -10,9 +10,20 @@
  * case explicitly.
  */
 
-import { BailianError, ExitCode, isInteractive } from "bailian-cli-core";
+import { BailianError, ExitCode, isInteractive, type Config } from "bailian-cli-core";
 import { printCurrentCommandHelp, getExecutingCommandPath } from "../utils/command-help.ts";
 
+/**
+ * Build a command-usage string for the running command: `<binName> <path> <args>`.
+ * Both the product binary name and the command path come from the runtime, so
+ * callers never hardcode "bl" or their own path — the same code renders as
+ * `bl knowledge retrieve …` under bl and `rag retrieve …` under rag.
+ */
+export function cmdUsage(config: Config, args = ""): string {
+  const parts = [config.binName, ...getExecutingCommandPath()].filter(Boolean);
+  return args ? `${parts.join(" ")} ${args}` : parts.join(" ");
+}
+
 // Dynamic import to avoid loading @clack/prompts in non-interactive envs unnecessarily
 // (though for CLI tools the startup cost is usually acceptable)
 

packages/runtime/src/registry.ts

@@ -165,7 +165,7 @@ export class CommandRegistry {
     }
 
     if (node.command) {
-      this.printCommandHelp(node.command, out);
+      this.printCommandHelp(node.command, commandPath, out);
       return;
     }
 
@@ -244,13 +244,17 @@ ${b("Getting Help:")}
 `);
   }
 
-  private printCommandHelp(cmd: Command, out: NodeJS.WriteStream): void {
+  private printCommandHelp(cmd: Command, commandPath: string[], out: NodeJS.WriteStream): void {
     const b = (s: string) => this.bold(s, out);
     const a = (s: string) => this.accent(s, out);
     const d = (s: string) => this.dim(s, out);
 
+    // `<bin> <path>` prefix is rendered here, not stored in the command, so the
+    // same command shows the right invocation under any product (bl / rag / …).
+    const prefix = [this.cliName, ...commandPath].join(" ");
+
     out.write(`\n${cmd.description}\n`);
-    if (cmd.usage) out.write(`${b("Usage:")} ${cmd.usage}\n`);
+    out.write(`${b("Usage:")} ${prefix}${cmd.usageArgs ? ` ${cmd.usageArgs}` : ""}\n`);
     if (cmd.options && cmd.options.length > 0) {
       const maxLen = Math.max(...cmd.options.map((o) => o.flag.length));
       out.write(`\n${b("Options:")}\n`);
@@ -264,10 +268,10 @@ ${b("Getting Help:")}
         out.write(`  ${note}\n`);
       }
     }
-    if (cmd.examples && cmd.examples.length > 0) {
+    if (cmd.exampleArgs && cmd.exampleArgs.length > 0) {
       out.write(`\n${b("Examples:")}\n`);
-      for (const ex of cmd.examples) {
-        out.write(`  ${d(ex)}\n`);
+      for (const ex of cmd.exampleArgs) {
+        out.write(`  ${d(ex ? `${prefix} ${ex}` : prefix)}\n`);
       }
     }
     out.write(