Added features

Added: 
Project Overview TUI 
Build Cache / Dirty Detection
Post-Build Hooks
gbuild status

include/cache.h

@@ -0,0 +1,35 @@
+#ifndef CACHE_H
+#define CACHE_H
+
+/*
+ * Build cache — per-project dirty detection.
+ *
+ * A small dotfile (.gbuild_cache) is kept inside each cloned repo dir.
+ * It stores the git HEAD hash that was current at the last *successful*
+ * build.  On the next run gbuild compares the live HEAD to the cached
+ * one; if they match the build is skipped unless --force was passed.
+ *
+ * Format of .gbuild_cache (plain text, one line):
+ *   <40-char sha1>\n
+ */
+
+#include <stddef.h>
+
+/* Maximum length of a stored hash (SHA-1 hex + NUL). */
+#define CACHE_HASH_LEN 64
+
+/*
+ * Read the cached hash for the repo at repo_path into out (>= CACHE_HASH_LEN
+ * bytes).  Returns 0 on success, -1 if the file does not exist or is
+ * unreadable (out is set to an empty string in that case).
+ */
+int cache_read(const char *repo_path, char *out, size_t n);
+
+/*
+ * Write hash as the new cached HEAD for the repo at repo_path.
+ * Creates or overwrites .gbuild_cache inside repo_path.
+ * Returns 0 on success, -1 on error.
+ */
+int cache_write(const char *repo_path, const char *hash);
+
+#endif /* CACHE_H */