Fix/gamelauncher nixos build (#225)

* game-launcher: bundle self-contained SQLite reader, drop libsqlite3 dependency

Fixes building gamelauncher.c on NixOS where the runtime env lacks
sqlite3.h/libsqlite3. scan_lutris now reads Lutris' pga.db through a
bundled read-only SQLite file parser instead of linking sqlite3.

* game-launcher: rework /g provider to reuse panel scan results

The launcher provider now reads the games the panel already scanned via
state/cache, trims the query, and surfaces status/error rows instead of
duplicating the scan.

---------

Co-authored-by: Ahmed5Emad <ahmed5emad@users.noreply.github.com>

game-launcher/sqlite_reader.h

@@ -0,0 +1,40 @@
+#ifndef GAME_LAUNCHER_SQLITE_READER_H
+#define GAME_LAUNCHER_SQLITE_READER_H
+
+#include <stddef.h>
+
+#define SQ_MAX_COLS 64
+
+typedef struct {
+    unsigned char *data;
+    size_t size;
+    int page_size;
+    int reserved;
+} SqliteDb;
+
+typedef struct {
+    int rootpage;
+    int ncols;
+    char colnames[SQ_MAX_COLS][64];
+    int id_is_rowid;
+} SqliteTable;
+
+typedef struct {
+    long long serial[SQ_MAX_COLS];
+    int n;
+} SqliteRecHeader;
+
+int sq_open(SqliteDb *db, const char *path);
+void sq_close(SqliteDb *db);
+
+int sq_find_table(SqliteDb *db, const char *name, SqliteTable *out);
+int sq_column_index(const SqliteTable *t, const char *name);
+
+typedef int (*sq_row_cb)(void *ctx, long long rowid, const unsigned char *rec, int reclen);
+int sq_walk_table(SqliteDb *db, int rootpage, sq_row_cb cb, void *ctx);
+
+int sq_parse_header(const unsigned char *rec, int reclen, SqliteRecHeader *h);
+int sq_col_text(const SqliteRecHeader *h, const unsigned char *rec, int reclen, int col, char *out, int outsz);
+long long sq_col_int(const SqliteRecHeader *h, const unsigned char *rec, int reclen, int col);
+
+#endif