feat: Hermit 1.1.0 — HERMIT_* env, Tauri desktop shell

Wire hermit_getenv across the engine, rebrand WebUI/systemd/docs, and
add apps/desktop (Tauri 2 + React) with a DeepSeek-Harness-like UI.
Qt app/ is frozen; full libcstcore FFI is scaffolded behind --features engine.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/model_registry.c

@@ -1,5 +1,6 @@
 #include "cst_models.h"
 #include "cst_util.h"
+#include "cst_hermit_glyph.h"
 
 #include "cJSON.h"
 #include "os_compat.h"
@@ -552,7 +553,7 @@ const cst_provider_t *cst_provider_find(const char *name) {
 }
 
 const cst_provider_t *cst_provider_default(void) {
-  const cst_provider_t *p = cst_provider_find(getenv("CST_PROVIDER"));
+  const cst_provider_t *p = cst_provider_find(hermit_getenv("PROVIDER"));
   return p ? p : cst_provider_at(0);
 }
 
@@ -606,7 +607,7 @@ int cst_models_list(const char *current, char out[][128], int max_out) {
   if (!out || max_out <= 0)
     return 0;
   int n = 0;
-  const char *env = getenv("CST_MODELS");
+  const char *env = hermit_getenv("MODELS");
   if (env && env[0]) {
     char buf[1024];
     snprintf(buf, sizeof(buf), "%s", env);
@@ -745,7 +746,7 @@ static void apply_cache(const char *provider, const char *model,
 }
 
 static int env_price(cst_price_t *out) {
-  const char *e = getenv("CST_PRICE");
+  const char *e = hermit_getenv("PRICE");
   if (!e || !e[0])
     return -1;
   memset(out, 0, sizeof(*out));
@@ -765,7 +766,7 @@ void cst_model_info(const char *provider, const char *model,
   memset(out, 0, sizeof(*out));
   out->vision = -1;
   unsigned have = 0;
-  const char *e = getenv("CST_CTX_TOKENS");
+  const char *e = hermit_getenv("CTX_TOKENS");
   if (e && atol(e) > 0) {
     out->context = atol(e);
     have |= F_CONTEXT;
@@ -857,7 +858,7 @@ void cst_model_caps(const char *provider, const char *api_base,
   cst_model_info_t mi;
   cst_model_info(provider, model, &mi);
   out->vision = mi.vision;
-  const char *e = getenv("CST_NO_CACHE_HINTS");
+  const char *e = hermit_getenv("NO_CACHE_HINTS");
   if ((e && e[0] == '1') || !model)
     return;
   out->cache_style = mi.cache_style;