chore: auto-commit (13 archivos)

- CMakeLists.txt
- agent_protocol.cpp
- agent_protocol.h
- app.md
- appicon.ico
- hosts_db.cpp
- hosts_db.h
- http_client.cpp
- http_client.h
- main.cpp
- ...

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

samples_db.h

@@ -0,0 +1,39 @@
+#pragma once
+#include <string>
+#include <vector>
+#include <cstdint>
+
+struct sqlite3;
+
+namespace pex {
+
+struct Sample {
+    int64_t host_id = 0;
+    int64_t unix_ts = 0;
+    float cpu_pct = 0.0f;
+    float ram_used_mb = 0.0f;
+    float ram_total_mb = 0.0f;
+    float disk_read_mb_s = 0.0f;
+    float disk_write_mb_s = 0.0f;
+    float net_rx_mb_s = 0.0f;
+    float net_tx_mb_s = 0.0f;
+    float gpu_pct = 0.0f;
+};
+
+class SamplesDb {
+public:
+    SamplesDb();
+    ~SamplesDb();
+
+    bool open(const std::string& path);
+    void close();
+
+    bool insert(const Sample& s);
+    // Devuelve muestras del host en ventana [unix_from, unix_to], ordenadas asc.
+    std::vector<Sample> query_range(int64_t host_id, int64_t unix_from, int64_t unix_to);
+
+private:
+    sqlite3* db_ = nullptr;
+};
+
+} // namespace pex