fix(plugins): remove unreachable hermes tools → Langfuse path

The langfuse plugin is hooks-only (no toolsets), so it never appears in
`hermes tools` — that menu iterates `_get_effective_configurable_toolsets()`
(= `CONFIGURABLE_TOOLSETS` + plugin-registered toolsets), and "langfuse"
is in neither. The `TOOL_CATEGORIES["langfuse"]` setup wizard (with its
`post_setup: "langfuse"` hook that pip-installs the SDK and writes
`plugins.enabled`) was reachable only when a toolset key "langfuse" got
enabled, which can't happen — so it's been dead code, and the docs that
promised "Setup (interactive): hermes tools → Langfuse Observability"
were silently broken.

Right home for that wizard is `hermes plugins` (e.g. auto-running a
plugin's post-setup hook on enable), which is a generic plugin-setup
mechanism worth designing properly rather than shoehorning langfuse
back into `hermes tools`. Until that exists, point users at the
working manual flow.

Code:
- Delete `TOOL_CATEGORIES["langfuse"]` (24 lines) — unreachable.
- Delete the `post_setup_key == "langfuse"` branch in `_run_post_setup`
  (29 lines) — only caller was the deleted TOOL_CATEGORIES entry.

Docs / comments (point at the manual flow + interactive `hermes plugins`):
- `plugins/observability/langfuse/README.md`: collapse the two-option
  setup section to the single working flow.
- `plugins/observability/langfuse/plugin.yaml`: update `description`.
- `plugins/observability/langfuse/__init__.py`: update module docstring.
- `hermes_cli/config.py`: update inline comment above the LANGFUSE_*
  env-var allow-list.
- `website/docs/user-guide/features/built-in-plugins.md`: collapse
  "Setup (interactive)" + "Setup (manual)" into one accurate block.
- `website/docs/reference/environment-variables.md`: update the
  cross-reference in the Langfuse env-vars section.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

hermes_cli/config.py

@@ -134,8 +134,7 @@ _EXTRA_ENV_KEYS = frozenset({
     "MATRIX_RECOVERY_KEY",
     # Langfuse observability plugin — optional tuning keys + standard SDK vars.
     # Activation is via plugins.enabled (opt-in through `hermes plugins enable
-    # observability/langfuse` or `hermes tools → Langfuse`); credentials gate
-    # the plugin at runtime.
+    # observability/langfuse`); credentials gate the plugin at runtime.
     "HERMES_LANGFUSE_ENV",
     "HERMES_LANGFUSE_RELEASE",
     "HERMES_LANGFUSE_SAMPLE_RATE",

hermes_cli/tools_config.py

@@ -461,31 +461,6 @@ TOOL_CATEGORIES = {
             },
         ],
     },
-    "langfuse": {
-        "name": "Langfuse Observability",
-        "icon": "📊",
-        "providers": [
-            {
-                "name": "Langfuse Cloud",
-                "tag": "Hosted Langfuse (cloud.langfuse.com)",
-                "env_vars": [
-                    {"key": "HERMES_LANGFUSE_PUBLIC_KEY", "prompt": "Langfuse public key (pk-lf-...)", "url": "https://cloud.langfuse.com"},
-                    {"key": "HERMES_LANGFUSE_SECRET_KEY", "prompt": "Langfuse secret key (sk-lf-...)", "url": "https://cloud.langfuse.com"},
-                ],
-                "post_setup": "langfuse",
-            },
-            {
-                "name": "Langfuse Self-Hosted",
-                "tag": "Self-hosted Langfuse instance",
-                "env_vars": [
-                    {"key": "HERMES_LANGFUSE_PUBLIC_KEY", "prompt": "Langfuse public key (pk-lf-...)"},
-                    {"key": "HERMES_LANGFUSE_SECRET_KEY", "prompt": "Langfuse secret key (sk-lf-...)"},
-                    {"key": "HERMES_LANGFUSE_BASE_URL", "prompt": "Langfuse server URL (e.g. http://localhost:3000)", "default": "http://localhost:3000"},
-                ],
-                "post_setup": "langfuse",
-            },
-        ],
-    },
 }
 
 # Simple env-var requirements for toolsets NOT in TOOL_CATEGORIES.
@@ -947,36 +922,6 @@ def _run_post_setup(post_setup_key: str):
             _print_warning(f"    Spotify login failed: {exc}")
             _print_info("    Run manually: hermes auth spotify")
 
-    elif post_setup_key == "langfuse":
-        # Install the langfuse SDK.
-        try:
-            __import__("langfuse")
-            _print_success("    langfuse SDK already installed")
-        except ImportError:
-            _print_info("    Installing langfuse SDK...")
-            result = _pip_install(["langfuse", "--quiet"], timeout=120)
-            if result.returncode == 0:
-                _print_success("    langfuse SDK installed")
-            else:
-                _print_warning("    langfuse SDK install failed — run manually: uv pip install langfuse")
-        # Opt the bundled observability/langfuse plugin into plugins.enabled.
-        # The plugin ships in the repo but doesn't load until the user enables
-        # it (standalone plugins are opt-in).
-        try:
-            from hermes_cli.plugins_cmd import _get_enabled_set, _save_enabled_set
-            enabled = _get_enabled_set()
-            if "observability/langfuse" in enabled or "langfuse" in enabled:
-                _print_success("    Plugin observability/langfuse already enabled")
-            else:
-                enabled.add("observability/langfuse")
-                _save_enabled_set(enabled)
-                _print_success("    Plugin observability/langfuse enabled")
-        except Exception as exc:
-            _print_warning(f"    Could not enable plugin automatically: {exc}")
-            _print_info("    Run manually: hermes plugins enable observability/langfuse")
-        _print_info("    Restart Hermes for tracing to take effect.")
-        _print_info("    Verify: hermes plugins list")
-
     elif post_setup_key == "xai_grok":
         # Shared credential bootstrap for any picker entry that talks to xAI
         # (TTS, Video Gen, future Image Gen, etc.). Accepts either a