feat(cli): two-stage /model autocomplete with ghost text suggestions (#1641)

* feat(cli): two-stage /model autocomplete with ghost text suggestions

- SlashCommandCompleter: Tab-complete providers first (anthropic:, openrouter:, etc.)
  then models within the selected provider
- SlashCommandAutoSuggest: inline ghost text for slash commands, subcommands,
  and /model provider:model two-stage suggestions
- Custom Tab key binding: accepts provider completion and immediately
  re-triggers completions to show that provider's models
- COMMANDS_BY_CATEGORY: structured format with explicit subcommands for
  tab completion and ghost text (prompt, reasoning, voice, skills, cron, browser)
- SUBCOMMANDS dict auto-extracted from command definitions
- Model/provider info cached 60s for responsive completions

* fix: repair test regression and restore gold color from PR #1622

- Fix test_unknown_command_still_shows_error: patch _cprint instead of
  console.print to match the _cprint switch in process_command()
- Restore gold color on 'Type /help' hint using _DIM + _GOLD constants
  instead of bare \033[2m (was losing the #B8860B gold)
- Use _GOLD constant for ambiguous command message for consistency
- Add clarifying comment on SUBCOMMANDS regex fallback

---------

Co-authored-by: Lars van der Zande <lmvanderzande@gmail.com>

tests/hermes_cli/test_commands.py

@@ -9,6 +9,8 @@ from hermes_cli.commands import (
     COMMANDS_BY_CATEGORY,
     CommandDef,
     GATEWAY_KNOWN_COMMANDS,
+    SUBCOMMANDS,
+    SlashCommandAutoSuggest,
     SlashCommandCompleter,
     gateway_help_lines,
     resolve_command,
@@ -323,3 +325,182 @@ class TestSlashCommandCompleter:
         completions = _completions(completer, "/no-desc")
         assert len(completions) == 1
         assert "Skill command" in completions[0].display_meta_text
+
+
+# ── SUBCOMMANDS extraction ──────────────────────────────────────────────
+
+
+class TestSubcommands:
+    def test_explicit_subcommands_extracted(self):
+        """Commands with explicit subcommands on CommandDef are extracted."""
+        assert "/prompt" in SUBCOMMANDS
+        assert "clear" in SUBCOMMANDS["/prompt"]
+
+    def test_reasoning_has_subcommands(self):
+        assert "/reasoning" in SUBCOMMANDS
+        subs = SUBCOMMANDS["/reasoning"]
+        assert "high" in subs
+        assert "show" in subs
+        assert "hide" in subs
+
+    def test_voice_has_subcommands(self):
+        assert "/voice" in SUBCOMMANDS
+        assert "on" in SUBCOMMANDS["/voice"]
+        assert "off" in SUBCOMMANDS["/voice"]
+
+    def test_cron_has_subcommands(self):
+        assert "/cron" in SUBCOMMANDS
+        assert "list" in SUBCOMMANDS["/cron"]
+        assert "add" in SUBCOMMANDS["/cron"]
+
+    def test_commands_without_subcommands_not_in_dict(self):
+        """Plain commands should not appear in SUBCOMMANDS."""
+        assert "/help" not in SUBCOMMANDS
+        assert "/quit" not in SUBCOMMANDS
+        assert "/clear" not in SUBCOMMANDS
+
+
+# ── Subcommand tab completion ───────────────────────────────────────────
+
+
+class TestSubcommandCompletion:
+    def test_subcommand_completion_after_space(self):
+        """Typing '/reasoning ' then Tab should show subcommands."""
+        completions = _completions(SlashCommandCompleter(), "/reasoning ")
+        texts = {c.text for c in completions}
+        assert "high" in texts
+        assert "show" in texts
+
+    def test_subcommand_prefix_filters(self):
+        """Typing '/reasoning sh' should only show 'show'."""
+        completions = _completions(SlashCommandCompleter(), "/reasoning sh")
+        texts = {c.text for c in completions}
+        assert texts == {"show"}
+
+    def test_subcommand_exact_match_suppressed(self):
+        """Typing the full subcommand shouldn't re-suggest it."""
+        completions = _completions(SlashCommandCompleter(), "/reasoning show")
+        texts = {c.text for c in completions}
+        assert "show" not in texts
+
+    def test_no_subcommands_for_plain_command(self):
+        """Commands without subcommands yield nothing after space."""
+        completions = _completions(SlashCommandCompleter(), "/help ")
+        assert completions == []
+
+
+# ── Two-stage /model completion ─────────────────────────────────────────
+
+
+def _model_completer() -> SlashCommandCompleter:
+    """Build a completer with mock model/provider info."""
+    return SlashCommandCompleter(
+        model_completer_provider=lambda: {
+            "current_provider": "openrouter",
+            "providers": {
+                "anthropic": "Anthropic",
+                "openrouter": "OpenRouter",
+                "nous": "Nous Research",
+            },
+            "models_for": lambda p: {
+                "anthropic": ["claude-sonnet-4-20250514", "claude-opus-4-20250414"],
+                "openrouter": ["anthropic/claude-sonnet-4", "google/gemini-2.5-pro"],
+                "nous": ["hermes-3-llama-3.1-405b"],
+            }.get(p, []),
+        }
+    )
+
+
+class TestModelCompletion:
+    def test_stage1_shows_providers(self):
+        completions = _completions(_model_completer(), "/model ")
+        texts = {c.text for c in completions}
+        assert "anthropic:" in texts
+        assert "openrouter:" in texts
+        assert "nous:" in texts
+
+    def test_stage1_current_provider_last(self):
+        completions = _completions(_model_completer(), "/model ")
+        texts = [c.text for c in completions]
+        assert texts[-1] == "openrouter:"
+
+    def test_stage1_current_provider_labeled(self):
+        completions = _completions(_model_completer(), "/model ")
+        for c in completions:
+            if c.text == "openrouter:":
+                assert "current" in c.display_meta_text.lower()
+                break
+        else:
+            raise AssertionError("openrouter: not found in completions")
+
+    def test_stage1_prefix_filters(self):
+        completions = _completions(_model_completer(), "/model an")
+        texts = {c.text for c in completions}
+        assert texts == {"anthropic:"}
+
+    def test_stage2_shows_models(self):
+        completions = _completions(_model_completer(), "/model anthropic:")
+        texts = {c.text for c in completions}
+        assert "anthropic:claude-sonnet-4-20250514" in texts
+        assert "anthropic:claude-opus-4-20250414" in texts
+
+    def test_stage2_prefix_filters_models(self):
+        completions = _completions(_model_completer(), "/model anthropic:claude-s")
+        texts = {c.text for c in completions}
+        assert "anthropic:claude-sonnet-4-20250514" in texts
+        assert "anthropic:claude-opus-4-20250414" not in texts
+
+    def test_stage2_no_model_provider_returns_empty(self):
+        completions = _completions(SlashCommandCompleter(), "/model ")
+        assert completions == []
+
+
+# ── Ghost text (SlashCommandAutoSuggest) ────────────────────────────────
+
+
+def _suggestion(text: str, completer=None) -> str | None:
+    """Get ghost text suggestion for given input."""
+    suggest = SlashCommandAutoSuggest(completer=completer)
+    doc = Document(text=text)
+
+    class FakeBuffer:
+        pass
+
+    result = suggest.get_suggestion(FakeBuffer(), doc)
+    return result.text if result else None
+
+
+class TestGhostText:
+    def test_command_name_suggestion(self):
+        """/he → 'lp'"""
+        assert _suggestion("/he") == "lp"
+
+    def test_command_name_suggestion_reasoning(self):
+        """/rea → 'soning'"""
+        assert _suggestion("/rea") == "soning"
+
+    def test_no_suggestion_for_complete_command(self):
+        assert _suggestion("/help") is None
+
+    def test_subcommand_suggestion(self):
+        """/reasoning h → 'igh'"""
+        assert _suggestion("/reasoning h") == "igh"
+
+    def test_subcommand_suggestion_show(self):
+        """/reasoning sh → 'ow'"""
+        assert _suggestion("/reasoning sh") == "ow"
+
+    def test_no_suggestion_for_non_slash(self):
+        assert _suggestion("hello") is None
+
+    def test_model_stage1_ghost_text(self):
+        """/model a → 'nthropic:'"""
+        completer = _model_completer()
+        assert _suggestion("/model a", completer=completer) == "nthropic:"
+
+    def test_model_stage2_ghost_text(self):
+        """/model anthropic:cl → rest of first matching model"""
+        completer = _model_completer()
+        s = _suggestion("/model anthropic:cl", completer=completer)
+        assert s is not None
+        assert s.startswith("aude-")