fix(deepseek): remap retired chat/reasoner aliases to v4-flash

DeepSeek cut off deepseek-chat and deepseek-reasoner on 2026-07-24.
Sending those IDs now returns HTTP 400; rewrite them (and fuzzy
reasoner names) to deepseek-v4-flash so saved configs keep working.

hermes_cli/model_normalize.py

@@ -12,9 +12,11 @@ Different LLM providers expect model identifiers in different formats:
   model IDs, but Claude still uses hyphenated native names like
   ``claude-sonnet-4-6``.
 - **OpenCode Go** preserves dots in model names: ``minimax-m2.7``.
-- **DeepSeek** accepts ``deepseek-chat`` (V3), ``deepseek-reasoner``
-  (R1-family), and the first-class V-series IDs (``deepseek-v4-pro``,
-  ``deepseek-v4-flash``, and any future ``deepseek-v<N>-*``).  Older
+- **DeepSeek** accepts only the first-class V-series IDs
+  (``deepseek-v4-pro``, ``deepseek-v4-flash``, and any future
+  ``deepseek-v<N>-*``).  The legacy aliases ``deepseek-chat`` and
+  ``deepseek-reasoner`` were retired on 2026-07-24 and are remapped to
+  ``deepseek-v4-flash`` (official non-thinking / thinking shims).  Older
   Hermes revisions folded every non-reasoner input into
   ``deepseek-chat``, which on aggregators routes to V3 — so a user
   picking V4 Pro was silently downgraded.
@@ -118,8 +120,9 @@ _LOWERCASE_MODEL_PROVIDERS: frozenset[str] = frozenset({
 # ---------------------------------------------------------------------------
 # DeepSeek special handling
 # ---------------------------------------------------------------------------
-# DeepSeek's API only recognises exactly two model identifiers.  We map
-# common aliases and patterns to the canonical names.
+# DeepSeek's direct API only accepts first-class V-series IDs after the
+# 2026-07-24 cut-off.  Legacy aliases and fuzzy names are remapped here so
+# saved configs / picker leftovers cannot keep sending retired IDs.
 
 _DEEPSEEK_REASONER_KEYWORDS: frozenset[str] = frozenset({
     "reasoner",
@@ -129,9 +132,15 @@ _DEEPSEEK_REASONER_KEYWORDS: frozenset[str] = frozenset({
     "cot",
 })
 
+# Retired on 2026-07-24 15:59 UTC. Official docs: both aliases mapped to
+# deepseek-v4-flash (chat = non-thinking, reasoner = thinking). Thinking
+# mode itself is controlled by extra_body.thinking on the DeepSeek profile.
+_DEEPSEEK_RETIRED_ALIASES: frozenset[str] = frozenset({
+    "deepseek-chat",
+    "deepseek-reasoner",
+})
+
 _DEEPSEEK_CANONICAL_MODELS: frozenset[str] = frozenset({
-    "deepseek-chat",       # V3 on DeepSeek direct and most aggregators
-    "deepseek-reasoner",   # R1-family reasoning model
     "deepseek-v4-pro",     # V4 Pro — first-class model ID
     "deepseek-v4-flash",   # V4 Flash — first-class model ID
 })
@@ -149,13 +158,15 @@ def _normalize_for_deepseek(model_name: str) -> str:
     """Map a model input to a DeepSeek-accepted identifier.
 
     Rules:
-    - Already a known canonical (``deepseek-chat``/``deepseek-reasoner``/
-      ``deepseek-v4-pro``/``deepseek-v4-flash``) -> pass through.
+    - Retired aliases ``deepseek-chat`` / ``deepseek-reasoner`` (cut off
+      2026-07-24) -> ``deepseek-v4-flash``.
+    - Already a known canonical (``deepseek-v4-pro``/``deepseek-v4-flash``)
+      -> pass through.
     - Matches the V-series pattern ``deepseek-v<digit>...`` -> pass through
       (covers future ``deepseek-v5-*`` and dated variants without a release).
     - Contains a reasoner keyword (r1, think, reasoning, cot, reasoner)
-      -> ``deepseek-reasoner``.
-    - Everything else -> ``deepseek-chat``.
+      -> ``deepseek-v4-flash``.
+    - Everything else -> ``deepseek-v4-flash``.
 
     Args:
         model_name: The bare model name (vendor prefix already stripped).
@@ -165,6 +176,11 @@ def _normalize_for_deepseek(model_name: str) -> str:
     """
     bare = _strip_vendor_prefix(model_name).lower()
 
+    # Retired aliases must rewrite — DeepSeek returns HTTP 400 after the
+    # 2026-07-24 cut-off if these IDs are sent on the wire.
+    if bare in _DEEPSEEK_RETIRED_ALIASES:
+        return "deepseek-v4-flash"
+
     if bare in _DEEPSEEK_CANONICAL_MODELS:
         return bare
 
@@ -175,9 +191,9 @@ def _normalize_for_deepseek(model_name: str) -> str:
     # Check for reasoner-like keywords anywhere in the name
     for keyword in _DEEPSEEK_REASONER_KEYWORDS:
         if keyword in bare:
-            return "deepseek-reasoner"
+            return "deepseek-v4-flash"
 
-    return "deepseek-chat"
+    return "deepseek-v4-flash"
 
 
 # ---------------------------------------------------------------------------
@@ -369,10 +385,13 @@ def normalize_model_for_provider(model_input: str, target_provider: str) -> str:
         'minimax-m2.5-free'
 
         >>> normalize_model_for_provider("deepseek-v3", "deepseek")
-        'deepseek-chat'
+        'deepseek-v4-flash'
 
         >>> normalize_model_for_provider("deepseek-r1", "deepseek")
-        'deepseek-reasoner'
+        'deepseek-v4-flash'
+
+        >>> normalize_model_for_provider("deepseek-reasoner", "deepseek")
+        'deepseek-v4-flash'
 
         >>> normalize_model_for_provider("my-model", "custom")
         'my-model'