feat: flatten opportunity commands, add config management, fix completions

- Flatten opportunity into top-level portfolio and opportunity commands
- Add interactive config get/set/key/secret with type coercion
- Rewrite --doc to show TUI vs JSON schema per command
- Unify agent mode output to JSON only
- Make init prompt for API key/secret interactively
- Fix coin tab completion alias binding
- Fix set_config_value reading from wrong path
- Fail loudly on invalid numeric config values

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/coinhunter/runtime.py

@@ -426,10 +426,7 @@ def _render_tui(payload: Any) -> None:
 
 def print_output(payload: Any, *, agent: bool = False) -> None:
     if agent:
-        if _is_large_dataset(payload):
-            _print_compact(payload)
-        else:
-            print_json(payload)
+        print_json(payload)
     else:
         _render_tui(payload)
 
@@ -509,6 +506,13 @@ def install_shell_completion(parser: argparse.ArgumentParser) -> dict[str, Any]:
         return {"shell": None, "installed": False, "reason": "unable to detect shell from $SHELL"}
 
     script = shtab.complete(parser, shell=shell, preamble="")
+    # Also register completion for the "coinhunter" alias
+    prog = parser.prog.replace("-", "_")
+    func = f"_shtab_{prog}"
+    if shell == "bash":
+        script += f"\ncomplete -o filenames -F {func} coinhunter\n"
+    elif shell == "zsh":
+        script += f"\ncompdef {func} coinhunter\n"
     installed_path: Path | None = None
     hint: str | None = None