Fix process memory provider base address sync and live refresh

Provider base address now stays in sync with tree base address when
changed via ChangeBase command, fixing reads from arbitrary memory
regions like KUSER_SHARED_DATA at 0x7FFE0000. ReadProcessMemory
handles partial reads gracefully. Snapshot extent uses tree-based
calculation instead of provider size to avoid oversized reads.
MCP source.switch gains pid parameter for programmatic process attach.
MCP server starts by default with logging and slow mode support.

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

src/mcp/mcp_bridge.h

@@ -20,6 +20,9 @@ public:
     void stop();
     bool isRunning() const { return m_server != nullptr; }
 
+    bool slowMode() const { return m_slowMode; }
+    void setSlowMode(bool v) { m_slowMode = v; }
+
     // Call from controller refresh / data change to notify MCP clients
     void notifyTreeChanged();
     void notifyDataChanged();
@@ -30,6 +33,7 @@ private:
     QLocalSocket*  m_client    = nullptr;  // single client for v1
     QByteArray     m_readBuffer;
     bool           m_initialized = false;
+    bool           m_slowMode    = false;
 
     // JSON-RPC plumbing
     void onNewConnection();