Add Case Advocate tab — partisan brief grounded in Norwegian law

New /advocate.php tab: user selects who they represent (biological
father, mother, foster carer, CWS, etc.) and the agent takes their
side entirely. Adversarial sub-questions target supporting Lovdata
statutes + ECHR precedents; synthesis returns client_strengths[] and
opposing_weaknesses[] alongside the advocate brief.

- DeepResearchAgent: add advocateRole param to run(), interpretSeed(),
  expandQueries(), synthesise(). Neutral path unchanged (empty string).
- api/deep-research.php: extract + validate advocate_role from payload;
  telemetry logs tool='advocate' vs 'deep_research'.
- advocate.php: new page with role dropdown (presets + custom), same
  corpus slices/engine/controls/upload zone as deep research.
- assets/js/advocate.js: page-scoped JS; renders advocate banner,
  client strengths card (teal), advocate brief, opposing weaknesses
  card (amber), sub-Q cards, sources, uncertainty, next step.
- assets/css/tools.css: append .adv-* rules (~120 lines).
- includes/layout.php: add Advocate nav tab between Deep research and
  Summarize.
- index.php: add Advocate cap-card tile.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

includes/DeepResearchAgent.php

@@ -30,7 +30,8 @@ final class DbnDeepResearchAgent
         string $engine,
         string $language,
         array  $controls,
-        ?callable $emit = null
+        ?callable $emit = null,
+        string $advocateRole = ''
     ): array {
         $seedQuery   = trim($seedQuery);
         $pastedText  = trim($pastedText);
@@ -81,14 +82,14 @@ final class DbnDeepResearchAgent
         // STEP 1: Query interpretation
         $emitRunning('interpretation', 'Query interpretation', 'Summarising the seed input…');
         $stepStart = microtime(true);
-        $interpretation = $this->interpretSeed($seedDescription, $language);
+        $interpretation = $this->interpretSeed($seedDescription, $language, $advocateRole);
         $this->stepTimings['interpretation'] = $this->elapsedMs($stepStart);
         $emitStep('interpretation', 'Query interpretation', $interpretation['detail'], 'complete');
 
         // STEP 2: Query expansion
         $emitRunning('expansion', 'Query expansion', 'Generating sub-questions…');
         $stepStart = microtime(true);
-        $expansion = $this->expandQueries($seedDescription, $interpretation['brief'], $controls['sub_q_count'], $language);
+        $expansion = $this->expandQueries($seedDescription, $interpretation['brief'], $controls['sub_q_count'], $language, $advocateRole);
         $this->stepTimings['expansion'] = $this->elapsedMs($stepStart);
         $subQuestions = $expansion['questions'];
         $expansionStatus = $expansion['fallback'] ? 'warning' : 'complete';
@@ -290,7 +291,8 @@ final class DbnDeepResearchAgent
             $numberedSources,
             $engine,
             $language,
-            $controls['temperature']
+            $controls['temperature'],
+            $advocateRole
         );
         $this->stepTimings['synthesis'] = $this->elapsedMs($stepStart);
         $emitStep(
@@ -335,10 +337,14 @@ final class DbnDeepResearchAgent
             ];
         }
 
+        $isAdvocate = $advocateRole !== '';
         return [
-            'tool'           => 'deep_research',
+            'tool'           => $isAdvocate ? 'advocate' : 'deep_research',
             'language'       => $language,
+            'advocate_role'  => $isAdvocate ? $advocateRole : null,
             'brief_markdown' => (string)($synthesis['json']['brief_markdown'] ?? $synthesis['json']['answer'] ?? ''),
+            'client_strengths'    => $isAdvocate ? ($synthesis['json']['client_strengths'] ?? []) : null,
+            'opposing_weaknesses' => $isAdvocate ? ($synthesis['json']['opposing_weaknesses'] ?? []) : null,
             'sub_questions'  => $subQOut,
             'sources'        => $numberedSources,
             'what_we_found'  => (string)($synthesis['json']['what_we_found'] ?? ''),
@@ -405,11 +411,14 @@ final class DbnDeepResearchAgent
         return implode("\n\n", $parts);
     }
 
-    private function interpretSeed(string $seedDescription, string $language): array
+    private function interpretSeed(string $seedDescription, string $language, string $advocateRole = ''): array
     {
         $locale = $language === 'no' ? 'Norwegian' : 'English';
+        $rolePrefix = $advocateRole !== ''
+            ? "You are preparing a case-research brief for: {$advocateRole}. Frame your interpretation to identify the strongest legal angles for this party.\n\n"
+            : '';
         $prompt = <<<PROMPT
-You are reviewing the input below to set up a deep legal research pass against the Do Better Norge family-law corpus.
+{$rolePrefix}You are reviewing the input below to set up a deep legal research pass against the Do Better Norge family-law corpus.
 
 Input:
 {$seedDescription}
@@ -445,10 +454,41 @@ PROMPT;
         ];
     }
 
-    private function expandQueries(string $seedDescription, string $brief, int $targetCount, string $language): array
+    private function expandQueries(string $seedDescription, string $brief, int $targetCount, string $language, string $advocateRole = ''): array
     {
         $locale = $language === 'no' ? 'Norwegian' : 'English';
-        $prompt = <<<PROMPT
+
+        if ($advocateRole !== '') {
+            $prompt = <<<PROMPT
+You are a Norwegian family-law research assistant building a case for: {$advocateRole}.
+Generate exactly {$targetCount} targeted sub-questions designed to find:
+1. Lovdata statutes and ECHR/Hague precedents that support {$advocateRole}'s position.
+2. Procedural rights and obligations the opposing party must satisfy — failures here help {$advocateRole}.
+3. Case law that exposes weaknesses in the opposing party's likely arguments.
+4. Specific articles, paragraphs, or judgments {$advocateRole}'s representative should cite.
+
+Research brief:
+{$brief}
+
+Raw input:
+{$seedDescription}
+
+Return JSON only in {$locale}:
+{
+  "sub_questions": [
+    {"id":"q1","question":"...","rationale":"how finding this strengthens {$advocateRole}'s case (≤ 140 chars)"}
+  ]
+}
+
+Rules:
+- Exactly {$targetCount} sub-questions, no more, no fewer.
+- Every question must be answerable from Norwegian family-law, child-welfare, or ECHR/Hague sources.
+- Each question must cover a DIFFERENT angle (supporting statute, procedural right, opposing weakness, ECHR precedent, evidentiary frame).
+- Sub-questions must be self-contained — readable without the raw input.
+- Write the questions in {$locale}.
+PROMPT;
+        } else {
+            $prompt = <<<PROMPT
 You are decomposing a Do Better Norge legal-research request into {$targetCount} focused sub-questions that should each be answered by the legal corpus (Norwegian family law, child welfare, ECHR/Hague).
 
 Research brief:
@@ -471,6 +511,7 @@ Rules:
 - Sub-questions must be self-contained — readable without seeing the seed text.
 - Write the questions in {$locale}.
 PROMPT;
+        }
 
         try {
             $raw = $this->azure->chatText([
@@ -790,7 +831,8 @@ PROMPT;
         array  $numberedSources,
         string $engine,
         string $language,
-        float  $temperature
+        float  $temperature,
+        string $advocateRole = ''
     ): array {
         $locale = $language === 'no' ? 'Norwegian' : 'English';
 
@@ -839,7 +881,44 @@ PROMPT;
             ? '400-900 words, minimum 4 paragraphs, with clear paragraph breaks. Cover EACH sub-question above in its own paragraph.'
             : '250-450 words, 2-3 short paragraphs. Note when evidence is thin.';
 
-        $prompt = <<<PROMPT
+        if ($advocateRole !== '') {
+            $prompt = <<<PROMPT
+You are Do Better Norge Legal Tools producing a legal preparation brief in {$locale}.
+Your client: {$advocateRole}
+
+You MUST ground every claim in the numbered sources below using inline `[n]` citation markers. Do NOT invent statutes, paragraph numbers, case names, dates, or parties.
+
+User input:
+{$seedDescription}
+
+Research brief:
+{$brief}
+{$subQText}
+
+Sources ({$sourceCount} numbered):
+{$sourcesText}
+
+Return JSON only in {$locale}:
+{
+  "brief_markdown": "Partisan but factually grounded advocate brief. {$lengthGuidance} Structure: (1) {$advocateRole}'s core legal position, (2) Strongest supporting arguments with [n] citations, (3) Identified weaknesses in the opposing party's position with [n] citations, (4) Procedural rights and obligations {$advocateRole} should assert. End with a one-line caveat that this is legal preparation support, not final legal advice.",
+  "client_strengths": ["3-6 strings — the strongest factual/legal points for {$advocateRole}, each anchored to at least one [n] source"],
+  "opposing_weaknesses": ["2-5 strings — vulnerabilities in the opposing position supported by retrieved sources. Omit this array entirely if evidence is thin — do NOT invent weaknesses."],
+  "what_we_found": "2-sentence summary of the most relevant retrieved authority for {$advocateRole}",
+  "what_remains_uncertain": ["3-5 gaps where evidence is insufficient or law is unclear — be honest"],
+  "next_practical_step": "one concrete action for {$advocateRole} to take next (legal filing, evidence gathering, consultation type, etc.)"
+}
+
+Rules:
+- Every factual claim in `brief_markdown` must end with one or more `[n]` markers.
+- If no source supports a point, omit the point — DO NOT speculate.
+- Prefer citing statute sections (e.g. "Barneloven §43") and case names verbatim from source excerpts.
+- When multiple sources support the same point, cite all of them (e.g. `[2,4]`).
+- `opposing_weaknesses` must be omitted or empty when no retrieved source actually supports the identified weakness.
+- Respond in {$locale}.
+- Output valid JSON only — no markdown fences around the JSON object itself.
+PROMPT;
+        } else {
+            $prompt = <<<PROMPT
 You are Do Better Norge Legal Tools running a deep-research synthesis. You MUST ground every claim in the numbered sources below, using inline `[n]` citation markers that map to the source list. Do NOT cite a source you did not use. Do NOT invent statutes, paragraph numbers, case names, dates, or parties.
 
 User input:
@@ -868,6 +947,7 @@ Rules:
 - Respond in {$locale}.
 - Output valid JSON only — no markdown fences around the JSON object itself.
 PROMPT;
+        }
 
         $messages = [
             ['role' => 'system', 'content' => 'You return valid JSON only. No markdown fences.'],