feat(skills): add skill config interface + llm-wiki skill (#5635)

Skills can now declare config.yaml settings via metadata.hermes.config
in their SKILL.md frontmatter. Values are stored under skills.config.*
namespace, prompted during hermes config migrate, shown in hermes config
show, and injected into the skill context at load time.

Also adds the llm-wiki skill (Karpathy's LLM Wiki pattern) as the first
skill to use the new config interface, declaring wiki.path.

Skill config interface (new):
- agent/skill_utils.py: extract_skill_config_vars(), discover_all_skill_config_vars(),
  resolve_skill_config_values(), SKILL_CONFIG_PREFIX
- agent/skill_commands.py: _inject_skill_config() injects resolved values
  into skill messages as [Skill config: ...] block
- hermes_cli/config.py: get_missing_skill_config_vars(), skill config
  prompting in migrate_config(), Skill Settings in show_config()

LLM Wiki skill (skills/research/llm-wiki/SKILL.md):
- Three-layer architecture (raw sources, wiki pages, schema)
- Three operations (ingest, query, lint)
- Session orientation, page thresholds, tag taxonomy, update policy,
  scaling guidance, log rotation, archiving workflow

Docs: creating-skills.md, configuration.md, skills.md, skills-catalog.md

Closes #5100

hermes_cli/config.py

@@ -1264,6 +1264,43 @@ def get_missing_config_fields() -> List[Dict[str, Any]]:
     return missing
 
 
+def get_missing_skill_config_vars() -> List[Dict[str, Any]]:
+    """Return skill-declared config vars that are missing or empty in config.yaml.
+
+    Scans all enabled skills for ``metadata.hermes.config`` entries, then checks
+    which ones are absent or empty under ``skills.config.<key>`` in the user's
+    config.yaml.  Returns a list of dicts suitable for prompting.
+    """
+    try:
+        from agent.skill_utils import discover_all_skill_config_vars, SKILL_CONFIG_PREFIX
+    except Exception:
+        return []
+
+    all_vars = discover_all_skill_config_vars()
+    if not all_vars:
+        return []
+
+    config = load_config()
+    missing: List[Dict[str, Any]] = []
+    for var in all_vars:
+        # Skill config is stored under skills.config.<logical_key>
+        storage_key = f"{SKILL_CONFIG_PREFIX}.{var['key']}"
+        parts = storage_key.split(".")
+        current = config
+        value = None
+        for part in parts:
+            if isinstance(current, dict) and part in current:
+                current = current[part]
+                value = current
+            else:
+                value = None
+                break
+        # Missing = key doesn't exist or is empty string
+        if value is None or (isinstance(value, str) and not value.strip()):
+            missing.append(var)
+    return missing
+
+
 def check_config_version() -> Tuple[int, int]:
     """
     Check config version.
@@ -1695,7 +1732,50 @@ def migrate_config(interactive: bool = True, quiet: bool = False) -> Dict[str, A
         config = load_config()
         config["_config_version"] = latest_ver
         save_config(config)
-    
+
+    # ── Skill-declared config vars ──────────────────────────────────────
+    # Skills can declare config.yaml settings they need via
+    # metadata.hermes.config in their SKILL.md frontmatter.
+    # Prompt for any that are missing/empty.
+    missing_skill_config = get_missing_skill_config_vars()
+    if missing_skill_config and interactive and not quiet:
+        print(f"\n  {len(missing_skill_config)} skill setting(s) not configured:")
+        for var in missing_skill_config:
+            skill_name = var.get("skill", "unknown")
+            print(f"    • {var['key']} — {var['description']} (from skill: {skill_name})")
+        print()
+        try:
+            answer = input("  Configure skill settings? [y/N]: ").strip().lower()
+        except (EOFError, KeyboardInterrupt):
+            answer = "n"
+
+        if answer in ("y", "yes"):
+            print()
+            config = load_config()
+            try:
+                from agent.skill_utils import SKILL_CONFIG_PREFIX
+            except Exception:
+                SKILL_CONFIG_PREFIX = "skills.config"
+            for var in missing_skill_config:
+                default = var.get("default", "")
+                default_hint = f" (default: {default})" if default else ""
+                value = input(f"  {var['prompt']}{default_hint}: ").strip()
+                if not value and default:
+                    value = str(default)
+                if value:
+                    storage_key = f"{SKILL_CONFIG_PREFIX}.{var['key']}"
+                    _set_nested(config, storage_key, value)
+                    results["config_added"].append(var["key"])
+                    print(f"  ✓ Saved {var['key']} = {value}")
+                else:
+                    results["warnings"].append(
+                        f"Skipped {var['key']} — skill '{var.get('skill', '?')}' may ask for it later"
+                    )
+                print()
+            save_config(config)
+        else:
+            print("  Set later with: hermes config set <key> <value>")
+
     return results
 
 
@@ -2349,6 +2429,23 @@ def show_config():
     print(f"  Telegram:     {'configured' if telegram_token else color('not configured', Colors.DIM)}")
     print(f"  Discord:      {'configured' if discord_token else color('not configured', Colors.DIM)}")
     
+    # Skill config
+    try:
+        from agent.skill_utils import discover_all_skill_config_vars, resolve_skill_config_values
+        skill_vars = discover_all_skill_config_vars()
+        if skill_vars:
+            resolved = resolve_skill_config_values(skill_vars)
+            print()
+            print(color("◆ Skill Settings", Colors.CYAN, Colors.BOLD))
+            for var in skill_vars:
+                key = var["key"]
+                value = resolved.get(key, "")
+                skill_name = var.get("skill", "")
+                display_val = str(value) if value else color("(not set)", Colors.DIM)
+                print(f"  {key:<20s} {display_val}  {color(f'[{skill_name}]', Colors.DIM)}")
+    except Exception:
+        pass
+
     print()
     print(color("─" * 60, Colors.DIM))
     print(color("  hermes config edit     # Edit config file", Colors.DIM))