feat: add poseidon/sisyphus/charizard skins + banner logo support

Adds 3 new built-in skins (poseidon, sisyphus, charizard) with full
customization — colors, spinner faces/verbs/wings, branding text, and
custom ASCII art banner logos. Total: 7 built-in skins.

Also adds banner_logo and banner_hero fields to SkinConfig, allowing
any skin to replace the HERMES-AGENT ASCII art logo and the caduceus
hero art with custom artwork. The CLI now renders the skin's logo when
available, falling back to the default Hermes logo.

Skins with custom logos: ares, poseidon, sisyphus, charizard
Skins using default logo: default, mono, slate

hermes_cli/skin_engine.py

@@ -111,6 +111,8 @@ class SkinConfig:
     spinner: Dict[str, Any] = field(default_factory=dict)
     branding: Dict[str, str] = field(default_factory=dict)
     tool_prefix: str = "┊"
+    banner_logo: str = ""    # Rich-markup ASCII art logo (replaces HERMES_AGENT_LOGO)
+    banner_hero: str = ""    # Rich-markup hero art (replaces HERMES_CADUCEUS)
 
     def get_color(self, key: str, fallback: str = "") -> str:
         """Get a color value with fallback."""
@@ -215,6 +217,12 @@ _BUILTIN_SKINS: Dict[str, Dict[str, Any]] = {
             "help_header": "(⚔) Available Commands",
         },
         "tool_prefix": "╎",
+        "banner_logo": """[bold #A3261F] █████╗ ██████╗ ███████╗███████╗       █████╗  ██████╗ ███████╗███╗   ██╗████████╗[/]
+[bold #B73122]██╔══██╗██╔══██╗██╔════╝██╔════╝      ██╔══██╗██╔════╝ ██╔════╝████╗  ██║╚══██╔══╝[/]
+[#C93C24]███████║██████╔╝█████╗  ███████╗█████╗███████║██║  ███╗█████╗  ██╔██╗ ██║   ██║[/]
+[#D84A28]██╔══██║██╔══██╗██╔══╝  ╚════██║╚════╝██╔══██║██║   ██║██╔══╝  ██║╚██╗██║   ██║[/]
+[#E15A2D]██║  ██║██║  ██║███████╗███████║      ██║  ██║╚██████╔╝███████╗██║ ╚████║   ██║[/]
+[#EB6C32]╚═╝  ╚═╝╚═╝  ╚═╝╚══════╝╚══════╝      ╚═╝  ╚═╝ ╚═════╝ ╚══════╝╚═╝  ╚═══╝   ╚═╝[/]""",
     },
     "mono": {
         "name": "mono",
@@ -278,6 +286,159 @@ _BUILTIN_SKINS: Dict[str, Dict[str, Any]] = {
         },
         "tool_prefix": "┊",
     },
+    "poseidon": {
+        "name": "poseidon",
+        "description": "Ocean-god theme — deep blue and seafoam",
+        "colors": {
+            "banner_border": "#2A6FB9",
+            "banner_title": "#A9DFFF",
+            "banner_accent": "#5DB8F5",
+            "banner_dim": "#153C73",
+            "banner_text": "#EAF7FF",
+            "ui_accent": "#5DB8F5",
+            "ui_label": "#A9DFFF",
+            "ui_ok": "#4caf50",
+            "ui_error": "#ef5350",
+            "ui_warn": "#ffa726",
+            "prompt": "#EAF7FF",
+            "input_rule": "#2A6FB9",
+            "response_border": "#5DB8F5",
+            "session_label": "#A9DFFF",
+            "session_border": "#496884",
+        },
+        "spinner": {
+            "waiting_faces": ["(≈)", "(Ψ)", "(∿)", "(◌)", "(◠)"],
+            "thinking_faces": ["(Ψ)", "(∿)", "(≈)", "(⌁)", "(◌)"],
+            "thinking_verbs": [
+                "charting currents", "sounding the depth", "reading foam lines",
+                "steering the trident", "tracking undertow", "plotting sea lanes",
+                "calling the swell", "measuring pressure",
+            ],
+            "wings": [
+                ["⟪≈", "≈⟫"],
+                ["⟪Ψ", "Ψ⟫"],
+                ["⟪∿", "∿⟫"],
+                ["⟪◌", "◌⟫"],
+            ],
+        },
+        "branding": {
+            "agent_name": "Poseidon Agent",
+            "welcome": "Welcome to Poseidon Agent! Type your message or /help for commands.",
+            "goodbye": "Fair winds! Ψ",
+            "response_label": " Ψ Poseidon ",
+            "prompt_symbol": "Ψ ❯ ",
+            "help_header": "(Ψ) Available Commands",
+        },
+        "tool_prefix": "│",
+        "banner_logo": """[bold #B8E8FF]██████╗  ██████╗ ███████╗██╗██████╗ ███████╗ ██████╗ ███╗   ██╗       █████╗  ██████╗ ███████╗███╗   ██╗████████╗[/]
+[bold #97D6FF]██╔══██╗██╔═══██╗██╔════╝██║██╔══██╗██╔════╝██╔═══██╗████╗  ██║      ██╔══██╗██╔════╝ ██╔════╝████╗  ██║╚══██╔══╝[/]
+[#75C1F6]██████╔╝██║   ██║███████╗██║██║  ██║█████╗  ██║   ██║██╔██╗ ██║█████╗███████║██║  ███╗█████╗  ██╔██╗ ██║   ██║[/]
+[#4FA2E0]██╔═══╝ ██║   ██║╚════██║██║██║  ██║██╔══╝  ██║   ██║██║╚██╗██║╚════╝██╔══██║██║   ██║██╔══╝  ██║╚██╗██║   ██║[/]
+[#2E7CC7]██║     ╚██████╔╝███████║██║██████╔╝███████╗╚██████╔╝██║ ╚████║      ██║  ██║╚██████╔╝███████╗██║ ╚████║   ██║[/]
+[#1B4F95]╚═╝      ╚═════╝ ╚══════╝╚═╝╚═════╝ ╚══════╝ ╚═════╝ ╚═╝  ╚═══╝      ╚═╝  ╚═╝ ╚═════╝ ╚══════╝╚═╝  ╚═══╝   ╚═╝[/]""",
+    },
+    "sisyphus": {
+        "name": "sisyphus",
+        "description": "Sisyphean theme — austere grayscale with persistence",
+        "colors": {
+            "banner_border": "#B7B7B7",
+            "banner_title": "#F5F5F5",
+            "banner_accent": "#E7E7E7",
+            "banner_dim": "#4A4A4A",
+            "banner_text": "#D3D3D3",
+            "ui_accent": "#E7E7E7",
+            "ui_label": "#D3D3D3",
+            "ui_ok": "#919191",
+            "ui_error": "#E7E7E7",
+            "ui_warn": "#B7B7B7",
+            "prompt": "#F5F5F5",
+            "input_rule": "#656565",
+            "response_border": "#B7B7B7",
+            "session_label": "#919191",
+            "session_border": "#656565",
+        },
+        "spinner": {
+            "waiting_faces": ["(◉)", "(◌)", "(◬)", "(⬤)", "(::)"],
+            "thinking_faces": ["(◉)", "(◬)", "(◌)", "(○)", "(●)"],
+            "thinking_verbs": [
+                "finding traction", "measuring the grade", "resetting the boulder",
+                "counting the ascent", "testing leverage", "setting the shoulder",
+                "pushing uphill", "enduring the loop",
+            ],
+            "wings": [
+                ["⟪◉", "◉⟫"],
+                ["⟪◬", "◬⟫"],
+                ["⟪◌", "◌⟫"],
+                ["⟪⬤", "⬤⟫"],
+            ],
+        },
+        "branding": {
+            "agent_name": "Sisyphus Agent",
+            "welcome": "Welcome to Sisyphus Agent! Type your message or /help for commands.",
+            "goodbye": "The boulder waits. ◉",
+            "response_label": " ◉ Sisyphus ",
+            "prompt_symbol": "◉ ❯ ",
+            "help_header": "(◉) Available Commands",
+        },
+        "tool_prefix": "│",
+        "banner_logo": """[bold #F5F5F5]███████╗██╗███████╗██╗   ██╗██████╗ ██╗  ██╗██╗   ██╗███████╗       █████╗  ██████╗ ███████╗███╗   ██╗████████╗[/]
+[bold #E7E7E7]██╔════╝██║██╔════╝╚██╗ ██╔╝██╔══██╗██║  ██║██║   ██║██╔════╝      ██╔══██╗██╔════╝ ██╔════╝████╗  ██║╚══██╔══╝[/]
+[#D7D7D7]███████╗██║███████╗ ╚████╔╝ ██████╔╝███████║██║   ██║███████╗█████╗███████║██║  ███╗█████╗  ██╔██╗ ██║   ██║[/]
+[#BFBFBF]╚════██║██║╚════██║  ╚██╔╝  ██╔═══╝ ██╔══██║██║   ██║╚════██║╚════╝██╔══██║██║   ██║██╔══╝  ██║╚██╗██║   ██║[/]
+[#8F8F8F]███████║██║███████║   ██║   ██║     ██║  ██║╚██████╔╝███████║      ██║  ██║╚██████╔╝███████╗██║ ╚████║   ██║[/]
+[#626262]╚══════╝╚═╝╚══════╝   ╚═╝   ╚═╝     ╚═╝  ╚═╝ ╚═════╝ ╚══════╝      ╚═╝  ╚═╝ ╚═════╝ ╚══════╝╚═╝  ╚═══╝   ╚═╝[/]""",
+    },
+    "charizard": {
+        "name": "charizard",
+        "description": "Volcanic theme — burnt orange and ember",
+        "colors": {
+            "banner_border": "#C75B1D",
+            "banner_title": "#FFD39A",
+            "banner_accent": "#F29C38",
+            "banner_dim": "#7A3511",
+            "banner_text": "#FFF0D4",
+            "ui_accent": "#F29C38",
+            "ui_label": "#FFD39A",
+            "ui_ok": "#4caf50",
+            "ui_error": "#ef5350",
+            "ui_warn": "#ffa726",
+            "prompt": "#FFF0D4",
+            "input_rule": "#C75B1D",
+            "response_border": "#F29C38",
+            "session_label": "#FFD39A",
+            "session_border": "#6C4724",
+        },
+        "spinner": {
+            "waiting_faces": ["(✦)", "(▲)", "(◇)", "(<>)", "(🔥)"],
+            "thinking_faces": ["(✦)", "(▲)", "(◇)", "(⌁)", "(🔥)"],
+            "thinking_verbs": [
+                "banking into the draft", "measuring burn", "reading the updraft",
+                "tracking ember fall", "setting wing angle", "holding the flame core",
+                "plotting a hot landing", "coiling for lift",
+            ],
+            "wings": [
+                ["⟪✦", "✦⟫"],
+                ["⟪▲", "▲⟫"],
+                ["⟪◌", "◌⟫"],
+                ["⟪◇", "◇⟫"],
+            ],
+        },
+        "branding": {
+            "agent_name": "Charizard Agent",
+            "welcome": "Welcome to Charizard Agent! Type your message or /help for commands.",
+            "goodbye": "Flame out! ✦",
+            "response_label": " ✦ Charizard ",
+            "prompt_symbol": "✦ ❯ ",
+            "help_header": "(✦) Available Commands",
+        },
+        "tool_prefix": "│",
+        "banner_logo": """[bold #FFF0D4] ██████╗██╗  ██╗ █████╗ ██████╗ ██╗███████╗ █████╗ ██████╗ ██████╗        █████╗  ██████╗ ███████╗███╗   ██╗████████╗[/]
+[bold #FFD39A]██╔════╝██║  ██║██╔══██╗██╔══██╗██║╚══███╔╝██╔══██╗██╔══██╗██╔══██╗      ██╔══██╗██╔════╝ ██╔════╝████╗  ██║╚══██╔══╝[/]
+[#F29C38]██║     ███████║███████║██████╔╝██║  ███╔╝ ███████║██████╔╝██║  ██║█████╗███████║██║  ███╗█████╗  ██╔██╗ ██║   ██║[/]
+[#E2832B]██║     ██╔══██║██╔══██║██╔══██╗██║ ███╔╝  ██╔══██║██╔══██╗██║  ██║╚════╝██╔══██║██║   ██║██╔══╝  ██║╚██╗██║   ██║[/]
+[#C75B1D]╚██████╗██║  ██║██║  ██║██║  ██║██║███████╗██║  ██║██║  ██║██████╔╝      ██║  ██║╚██████╔╝███████╗██║ ╚████║   ██║[/]
+[#7A3511] ╚═════╝╚═╝  ╚═╝╚═╝  ╚═╝╚═╝  ╚═╝╚═╝╚══════╝╚═╝  ╚═╝╚═╝  ╚═╝╚═════╝       ╚═╝  ╚═╝ ╚═════╝ ╚══════╝╚═╝  ╚═══╝   ╚═╝[/]""",
+    },
 }
 
 
@@ -326,6 +487,8 @@ def _build_skin_config(data: Dict[str, Any]) -> SkinConfig:
         spinner=spinner,
         branding=branding,
         tool_prefix=data.get("tool_prefix", default.get("tool_prefix", "┊")),
+        banner_logo=data.get("banner_logo", ""),
+        banner_hero=data.get("banner_hero", ""),
     )