feat: implement tier 1 quick wins (tool groups, typing, pruning, verbose, think)

Five additive features with no breaking changes:

- Tool groups: group:fs, group:runtime, group:web, group:memory syntactic
  sugar for allow/deny lists in tool policy config
- Typing indicators: Discord sendTyping() and WhatsApp sendStateTyping()
  on message receipt for better UX feedback
- Session pruning: TTL-based auto-cleanup via sessions.ttl config with
  hourly daemon timer and SQLite GROUP BY pruning
- /verbose command: TUI command parser toggle for raw streaming display
- !!think prefix: per-message extended thinking mode wired through
  Anthropic (budget_tokens), OpenAI/GitHub (reasoning_effort), and
  Gemini (thinkingConfig) providers

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

src/models/anthropic.ts

@@ -74,11 +74,21 @@ export class AnthropicClient implements ModelClient {
       params.tools = request.tools;
     }
 
+    // Extended thinking mode — enable thinking with a budget
+    if (request.thinking) {
+      params.max_tokens = Math.max(params.max_tokens as number, 16384);
+      (params as any).thinking = { type: 'enabled', budget_tokens: 4096 };
+    }
+
     const response = await this.client.messages.create(params as unknown as Parameters<typeof this.client.messages.create>[0]) as AnthropicMessage;
 
     const textContent = response.content.find((c) => c.type === 'text');
     const content = textContent?.type === 'text' ? textContent.text : '';
 
+    // Extract thinking content if present
+    const thinkingBlock = response.content.find((c) => c.type === 'thinking');
+    const thinkingContent = thinkingBlock && 'thinking' in thinkingBlock ? (thinkingBlock as any).text : undefined;
+
     const toolCalls = response.content
       .filter((c): c is { type: 'tool_use'; id: string; name: string; input: unknown } => c.type === 'tool_use')
       .map(c => ({ id: c.id, name: c.name, args: c.input }));
@@ -91,6 +101,7 @@ export class AnthropicClient implements ModelClient {
         outputTokens: response.usage.output_tokens,
       },
       ...(toolCalls.length > 0 ? { toolCalls } : {}),
+      ...(thinkingContent ? { thinkingContent } : {}),
     };
   }