Enable cross-repo navigation to project dependencies

Previously external-ns? only included clojure.* and java.* namespaces,
missing project dependencies like tui.events. This prevented cross-repo
go-to-definition from working.

Changes:
- external-ns? now considers any non-internal namespace as external
- collect-external-symbols creates symbol entries even without runtime docs
- This enables hover and go-to-definition for dependency symbols

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/scip_clojure/core.clj

@@ -206,13 +206,11 @@
      :special-form true}))
 
 (defn external-ns?
-  "Check if a namespace is external (standard library or dependency)."
+  "Check if a namespace is external (not defined in this project).
+   Any namespace not in internal-namespaces is considered external,
+   enabling cross-repo navigation to dependencies."
   [ns-sym internal-namespaces]
-  (let [ns-str (str ns-sym)]
-    (and (not (contains? internal-namespaces ns-sym))
-         (or (str/starts-with? ns-str "clojure.")
-             (str/starts-with? ns-str "java.")
-             (contains? external-ns-prefixes ns-str)))))
+  (not (contains? internal-namespaces ns-sym)))
 
 (defn get-var-doc
   "Get documentation for a var. Returns a map with :doc, :arglists, :macro.
@@ -236,7 +234,8 @@
       (catch Exception _ nil))))
 
 (defn external-symbol->symbol-info
-  "Create SCIP SymbolInformation for an external symbol with documentation."
+  "Create SCIP SymbolInformation for an external symbol.
+   Works with or without documentation - symbol entry is essential for cross-repo nav."
   [{:keys [ns name doc arglists macro special-form]}]
   (let [builder (Scip$SymbolInformation/newBuilder)
         sig (str (cond special-form "special form "
@@ -246,25 +245,29 @@
     (.setSymbol builder (make-symbol ns name))
     ;; Add signature as first doc line
     (.addDocumentation builder (str "```clojure\n" sig "\n```"))
-    ;; Add arglists
+    ;; Add arglists if available
     (when (seq arglists)
       (.addDocumentation builder (str "```clojure\n" (format-arglists arglists) "\n```")))
-    ;; Add docstring
+    ;; Add docstring if available
     (when doc
       (.addDocumentation builder doc))
     (.build builder)))
 
 (defn collect-external-symbols
-  "Collect all unique external symbol references from analysis."
+  "Collect all unique external symbol references from analysis.
+   Returns symbol info for all external symbols, with docs when available.
+   Essential for cross-repo navigation to dependencies."
   [analysis internal-namespaces]
   (->> (vals analysis)
        (mapcat :var-usages)
        (filter #(external-ns? (:to %) internal-namespaces))
        (map (fn [{:keys [to name]}] [to name]))
+       (filter (fn [[ns-sym _]] ns-sym))  ; Filter out nil namespaces
        (distinct)
-       (keep (fn [[ns-sym var-name]]
-               (get-var-doc ns-sym var-name)))
-       (filter :doc)))  ; Only include symbols with documentation
+       (map (fn [[ns-sym var-name]]
+              ;; Try to get docs, but always return at minimum ns/name
+              (or (get-var-doc ns-sym var-name)
+                  {:ns ns-sym :name var-name})))))
 
 (defn uri->relative-path
   "Convert file:// URI to relative path from project root."