Let General Chat search the web, and only General Chat

Search is the one capability that fits the profile holding none: every other capability either
reads this installation or changes it, and chat's whole contract is that it can do neither. The
assistant deliberately does not get it — its contract is that answers come from this install's
own documents, and a web result there is an answer that looks sourced and is not. A chat question
about this machine hands off to the assistant before the search would run, so it never reaches
the internet even with the box ticked.

Off by default, and not because it is dangerous: searching sends the operator's question outside
the house, which is theirs to decide. Asked for per turn as well as enabled in conf.

Provider-agnostic, as asked — searxng, brave, tavily. Only whichever is configured here can be
verified; all three read every field by name, so a shape that changes underneath yields no
results rather than wrong ones.

The explain fixtures asserted chat holds no capabilities at all, which is exactly the guarantee
worth keeping. caps=only: now states the set rather than its emptiness, so the check still fails
the day something else is granted there.

Plugin/unraid/Tools/ai_chat_worker.php

@@ -121,8 +121,8 @@ if ($explain) {
         exit(2);
     }
 } else {
-    [$jobFile, $question, $historyJson, $kind, $think, $profile, $scope] =
-        array_slice($argv, 1, 7) + array_fill(0, 7, '');
+    [$jobFile, $question, $historyJson, $kind, $think, $profile, $scope, $webArg] =
+        array_slice($argv, 1, 8) + array_fill(0, 8, '');
 
     if ($jobFile === '' || $question === '') exit(1);
     if (!preg_match('#/[0-9a-f]{32}\.json$#', $jobFile)) exit(1);
@@ -197,6 +197,49 @@ $sources   = [];
 $context   = '';
 $tRetrieve = 0.0;
 
+// ── Web search ───────────────────────────────────────────────────────────────────────────────
+// Asked for per turn, never decided here. The operator ticks it, and it only exists on the one
+// profile that holds the capability — which is General Chat, and only because chat cannot write.
+//
+// Placed ahead of retrieval so its results are numbered first and the citation numbers the model
+// sees match the order the page lists them in. It is mutually exclusive with retrieval in
+// practice rather than by rule: no profile holds both, because the assistant's contract is that
+// its answers come from this installation's own documents.
+//
+// A handoff has already happened by this point if it was going to — a chat question about this
+// machine has become a varaverk one, which does not hold web_search, so asking about Varaverk
+// never reaches the internet even with the box ticked.
+$webAsked = ($webArg ?? '') === '1';
+if ($webAsked && $can('web_search')) {
+    require_once dirname(__DIR__) . '/include/ai_web.php';
+    $tw  = microtime(true);
+    $web = vv_ai_web_search($question);
+    wlog(sprintf('web search provider=%s ok=%s results=%d %s(%dms)',
+        $web['provider'] ?? '?', ($web['ok'] ?? false) ? 'yes' : 'no',
+        count($web['results'] ?? []), isset($web['error']) ? '(' . $web['error'] . ') ' : '',
+        (int)((microtime(true) - $tw) * 1000)));
+
+    if (($web['ok'] ?? false) && $web['results']) {
+        $context .= vv_ai_web_context($web['results'], 0);
+        foreach ($web['results'] as $r) {
+            // path carries the URL so the existing citation wiring keeps working unchanged; url
+            // is what tells the page to open a browser tab instead of the source viewer.
+            $sources[] = ['path' => $r['url'], 'url' => $r['url'], 'section' => '',
+                          'heading' => $r['title'], 'score' => 0, 'web' => true];
+        }
+        $attached['web_search'] = count($web['results']) . ' results';
+    } elseif (!($web['ok'] ?? false)) {
+        // Told to the model rather than swallowed. An assistant that searched and got nothing
+        // must not answer as though it had searched and found nothing exists.
+        $context .= "A web search was requested but did not run: " . ($web['error'] ?? 'unknown')
+                  . ". Say so rather than answering as though the web had been consulted.\n\n";
+        $attached['web_search'] = 'failed: ' . ($web['error'] ?? 'unknown');
+    } else {
+        $context .= "A web search was run and returned no results. Say so.\n\n";
+        $attached['web_search'] = 'no results';
+    }
+}
+
 if ($can('retrieve')) {
     jw($jobFile, ['status' => 'retrieving']);
 
@@ -233,14 +276,19 @@ if ($can('retrieve')) {
 
     $tRetrieve = microtime(true) - $t0;
 
-    $sources = array_map(fn($x) => [
-        'path' => $x['path'] ?? '', 'section' => $x['section'] ?? '',
-        'heading' => $x['heading'] ?? '', 'score' => $x['score'] ?? 0,
-    ], $r['results']);
+    // Appended, and numbered from whatever is already there. No profile holds both web_search and
+    // retrieve, so today this offset is always zero — but assigning over $sources and numbering
+    // from one would silently drop the other set the moment one ever does, and a citation
+    // pointing at the wrong source is worse than no citation.
+    $offset = count($sources);
+    foreach ($r['results'] as $x) {
+        $sources[] = ['path' => $x['path'] ?? '', 'section' => $x['section'] ?? '',
+                      'heading' => $x['heading'] ?? '', 'score' => $x['score'] ?? 0];
+    }
 
     foreach ($r['results'] as $i => $x) {
         $label = implode(' › ', array_filter([$x['path'] ?? '', $x['section'] ?? '', $x['heading'] ?? '']));
-        $context .= '[' . ($i + 1) . '] ' . $label . "\n" . trim($x['content'] ?? '') . "\n\n";
+        $context .= '[' . ($offset + $i + 1) . '] ' . $label . "\n" . trim($x['content'] ?? '') . "\n\n";
     }
 }