Initial CST-Agent: portable Linux/Termux/Windows coding agent.

Vendored sashidown, OpenAI-compatible env (OPENAI_*), and bootstrap scripts.

Co-authored-by: Cursor <cursoragent@cursor.com>

vendor/sashidown/src/table_stats.h

@@ -0,0 +1,32 @@
+#ifndef MD_TABLE_STATS_H
+#define MD_TABLE_STATS_H
+
+#include "sashidown.h"
+#include <stddef.h>
+#include <stdint.h>
+
+#define SASHIDOWN_MAX_COLS 32
+
+/*
+ * [CST Pending Window Metadata] — lightweight table descriptor for the
+ * delayed-commitment pending window. Records header/separator/body bounds
+ * without caching cells; render rescans once after the separator enters
+ * the confirmation frontier. No per-cell heap; O(1) registers only.
+ */
+typedef struct {
+    size_t start;      /* header line start */
+    size_t end;        /* first byte after the table */
+    size_t body_start; /* first body row (after separator) */
+    int    cols;       /* column count from header (GFM) */
+    int    body_rows;
+    int    valid;
+} table_entry_t;
+
+int table_is_separator_row(const char *line, size_t len);
+int table_count_cols(const char *line, size_t len, int *has_pipe);
+
+/* ctx may be NULL (falls back to memchr); when non-NULL reuses line_index. */
+int table_try_parse_at(sashidown_ctx_t *ctx, const char *input, size_t len,
+                       size_t pos, table_entry_t *e);
+
+#endif /* MD_TABLE_STATS_H */