fix(linux): prevent segfaults during rapid module reloads

Fixes multiple issues causing segfaults when hot-reloading modules
on Linux, particularly when file changes are detected rapidly:

- Enable is_file_ready() check on Linux to prevent loading partially-written
  shared libraries (previously only used on Windows/BSD)
- Fix event deduplication on Linux to actually remove duplicate inotify events
  instead of just marking them, preventing double-free on same module
- Reorder reload operations to unload old module only after successfully
  copying new version, avoiding invalid state when copy fails

Changes:
- platform.c: Remove __linux__ guards around is_file_ready() function
- platform.c: Add compaction step after deduplication to remove -1 entries
- stk.c: Move module unload to after platform_copy_file() in reload loop

These changes make Linux hot-reload as robust as Windows/BSD implementations.

src/platform.c

@@ -32,7 +32,6 @@ int is_mod_loaded(const char *module_name);
 uint8_t is_valid_module_file(const char *filename);
 void extract_module_id(const char *path, char *out_id);
 
-#ifndef __linux__
 static uint8_t is_file_ready(const char *dir_path, const char *filename)
 {
 	char full_path[STK_PATH_MAX_OS];
@@ -80,6 +79,7 @@ static uint8_t is_file_ready(const char *dir_path, const char *filename)
 #endif
 }
 
+#ifndef __linux__
 typedef struct {
 	char filename[STK_PATH_MAX];
 #ifdef _WIN32
@@ -146,7 +146,6 @@ uint8_t platform_copy_file(const char *from, const char *to)
 	FILE *src = NULL, *dst = NULL;
 	char tmp_path[STK_PATH_MAX_OS];
 	size_t n;
-#ifndef __linux__
 	char dir_path[STK_PATH_MAX_OS];
 	const char *filename;
 
@@ -163,7 +162,6 @@ uint8_t platform_copy_file(const char *from, const char *to)
 
 	if (!is_file_ready(dir_path, filename))
 		goto done;
-#endif
 
 	sprintf(tmp_path, "%s.tmp", to);
 
@@ -286,11 +284,10 @@ void *platform_get_symbol(void *h, const char *s)
 #endif
 }
 
-char (*platform_directory_init_scan(const char *dir_path,
-				    size_t *out_count))[STK_PATH_MAX]
-{
+char (*platform_directory_init_scan(const char *dir_path, size_t *out_count))
+    [STK_PATH_MAX] {
 	    size_t count = 0, i = 0, name_len;
-	char(*list)[STK_PATH_MAX] = NULL;
+	    char (*list)[STK_PATH_MAX] = NULL;
 #ifdef _WIN32
 	    WIN32_FIND_DATAA fd;
 	    HANDLE h;
@@ -338,9 +335,9 @@ char (*platform_directory_init_scan(const char *dir_path,
 	    FindClose(h);
 	    goto exit;
 
-create_and_exit:
+    create_and_exit:
 	    platform_mkdir(dir_path);
-exit:
+    exit:
 	    *out_count = i;
 	    return list;
 #else
@@ -353,7 +350,7 @@ exit:
 	    if (!d)
 		    goto create_and_exit;
 
-count_loop:
+    count_loop:
 	    e = readdir(d);
 	    if (!e)
 		    goto count_done;
@@ -368,7 +365,7 @@ count_loop:
 	    count++;
 	    goto count_loop;
 
-count_done:
+    count_done:
 	    if (count == 0)
 		    goto close_and_exit;
 
@@ -377,7 +374,7 @@ count_done:
 	    if (!list)
 		    goto close_and_exit;
 
-fill_loop:
+    fill_loop:
 	    e = readdir(d);
 	    if (!e || i >= count)
 		    goto close_and_exit;
@@ -397,17 +394,17 @@ fill_loop:
 	    list[i - 1][name_len] = '\0';
 	    goto fill_loop;
 
-create_and_exit:
+    create_and_exit:
 	    platform_mkdir(dir_path);
 	    *out_count = 0;
 	    return NULL;
 
-close_and_exit:
+    close_and_exit:
 	    closedir(d);
 	    *out_count = i;
 	    return list;
 #endif
-}
+    }
 
 #if !defined(__linux__) && !defined(_WIN32)
 static void update_watches(platform_watch_context_t *ctx)
@@ -665,7 +662,7 @@ stk_module_event_t *platform_directory_watch_check(
 	int fd = (int)(long)handle;
 	char buf[STK_EVENT_BUFFER];
 	ssize_t len;
-	size_t index = 0, count = 0, i;
+	size_t index = 0, count = 0, i, write_idx;
 	stk_module_event_t *evs;
 	char *ptr, *end;
 	struct inotify_event *e;
@@ -763,6 +760,21 @@ stk_module_event_t *platform_directory_watch_check(
 		}
 	}
 
+	write_idx = 0;
+	for (i = 0; i < index; ++i) {
+		if (evs[i] != -1) {
+			if (write_idx != i) {
+				evs[write_idx] = evs[i];
+				strncpy((*file_list)[write_idx],
+					(*file_list)[i], STK_PATH_MAX - 1);
+				(*file_list)[write_idx][STK_PATH_MAX - 1] =
+				    '\0';
+			}
+			write_idx++;
+		}
+	}
+	index = write_idx;
+
 	*out_count = index;
 	return evs;
 

src/stk.c

@@ -242,9 +242,6 @@ begin_operations:
 	for (i = 0; i < unload_count; ++i)
 		stk_module_unload(unloaded_mod_indices[i]);
 
-	for (i = 0; i < reload_count; ++i)
-		stk_module_unload(reloaded_mod_indices[i]);
-
 	for (i = 0; i < reload_count; ++i) {
 		int file_index = reloaded_mod_file_indices[i];
 		int mod_index = reloaded_mod_indices[i];
@@ -261,6 +258,8 @@ begin_operations:
 			continue;
 		}
 
+		stk_module_unload(mod_index);
+
 		load_result = stk_module_load(tmp_path, mod_index);
 		if (load_result != STK_MOD_INIT_SUCCESS) {
 			stk_log(stderr, "Failed to reload module %s: %s",