feat(ai): discover the llama-swap picker and vision from model metadata

/insights/models now lists llama-swap's models live from /v1/models
instead of LLAMA_SWAP_ALLOWED_MODELS: every kind=chat model, with
setParamsByID aliases (:sub / :fast) hidden, filtered by
[llamacpp.picker] exclude and the optional include allowlist. Ids the
include list names but llama-swap no longer serves drop out instead of
showing as dead picker entries.

has_vision and context_window come from each model's config.yaml metadata
(read from meta.llamaswap, where the deployed llama-swap merges it, or from
meta as upstream documents). A model without metadata is text-only chat.
A live served window still wins over the configured ctx.

Agentic insights on llama-swap now ask the chat model's capabilities:
text-only models (e.g. qwen3.8-27b-code, --no-mmproj) get the local vision
model's description inlined, like hybrid, instead of an image they can't
read. If llama-swap can't be asked, images are sent as before.

Drops AppState.llamacpp_allowed_models.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/ai/handlers.rs

@@ -983,17 +983,15 @@ pub async fn generate_agentic_insight_handler(
 }
 
 /// GET /insights/models - Local-backend models with capabilities. Returns
-/// Ollama servers when `LLM_BACKEND=ollama` (default), or llama-swap slots
-/// when `LLM_BACKEND=llamacpp`. Same envelope shape either way so the
+/// Ollama servers when `backend = "ollama"` (default), or llama-swap models
+/// when `backend = "llamacpp"`. Same envelope shape either way so the
 /// client picker doesn't have to branch on backend kind.
 ///
-/// For llama-swap: `models` comes verbatim from `LLAMA_SWAP_ALLOWED_MODELS`
-/// (no live `/v1/models` probe), `has_vision` is true only for the
-/// configured `LLAMA_SWAP_VISION_MODEL` slot id, and `has_tool_calling` is
-/// reported as true for every slot (llama-server is launched with `--jinja`
-/// by convention — a misconfigured slot surfaces as a chat-call error).
-/// `context_window` is each slot's served `-c` window when known without
-/// loading the model (cached from a recent chat, or the model is running).
+/// For llama-swap: `models` is discovered live from `/v1/models` — every
+/// `kind: chat` model (aliases hidden) filtered by `[llamacpp.picker]` —
+/// with `has_vision` / `context_window` from each model's config.yaml
+/// `metadata`. A served window known without loading the model (cached from
+/// a recent chat, or the model is running) takes precedence over `ctx`.
 #[get("/insights/models")]
 pub async fn get_available_models_handler(
     _claims: Claims,
@@ -1004,20 +1002,30 @@ pub async fn get_available_models_handler(
     if crate::ai::local_backend_is_llamacpp()
         && let Some(lc) = app_state.llamacpp.as_ref()
     {
+        let picker = &crate::ai::config::llm_config().llamacpp.picker;
+        let mut models = match lc.discover_models().await {
+            Ok(found) => crate::ai::llamacpp::picker_models(found, picker),
+            Err(e) => {
+                // llama-swap is down, so chat would fail anyway; still list
+                // the configured model so the picker isn't empty when it
+                // comes back.
+                log::warn!("llama-swap model discovery failed: {e:#}");
+                vec![ModelCapabilities {
+                    name: lc.primary_model.clone(),
+                    has_vision: true,
+                    has_tool_calling: true,
+                    context_window: None,
+                }]
+            }
+        };
         // Served windows for the context picker; never loads a model.
-        let windows = lc
-            .known_context_windows(&app_state.llamacpp_allowed_models)
-            .await;
-        let models: Vec<ModelCapabilities> = app_state
-            .llamacpp_allowed_models
-            .iter()
-            .map(|name| ModelCapabilities {
-                name: name.clone(),
-                has_vision: true,
-                has_tool_calling: true,
-                context_window: windows.get(name).copied(),
-            })
-            .collect();
+        let names: Vec<String> = models.iter().map(|m| m.name.clone()).collect();
+        let windows = lc.known_context_windows(&names).await;
+        for m in &mut models {
+            if let Some(&n) = windows.get(&m.name) {
+                m.context_window = Some(n);
+            }
+        }
         let primary = ServerModels {
             url: lc.base_url.clone(),
             models,