fix: replace fixed output buffer with growable buffer in cross_project_links

The 58KB safety limit on a 64KB buffer caused the SQL result loop to
exit early, truncating output when many cross-project links exist
(e.g., 163 graphql links fill ~57KB, hiding all 142 pubsub links).

Replace with a dynamically growing buffer (realloc 2x when needed)
and a reserved header space to avoid the memmove headroom issue.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: Shidfar

src/mcp/mcp.c

@@ -3434,12 +3434,13 @@ static char *handle_cross_project_links(cbm_mcp_server_t *srv, const char *args)
         sqlite3_bind_text(stmt, bind_idx++, identifier, -1, SQLITE_STATIC);
     }
 
-    /* Format output */
-    enum { XL_BUF_SIZE = 65536 };
-    char *buf = malloc(XL_BUF_SIZE);
+    /* Format output — reserve 128 bytes at start for header (filled after loop) */
+    enum { XL_HDR_RESERVE = 128 };
+    int buf_cap = 65536;
+    char *buf = malloc((size_t)buf_cap);
     if (!buf) { sqlite3_finalize(stmt); sqlite3_close(db);
                  return cbm_mcp_text_result("alloc failed", true); }
-    int pos = 0;
+    int pos = XL_HDR_RESERVE;  /* start writing after header reservation */
     int total = 0;
     char cur_protocol[64] = {0};
     int proto_count = 0;
@@ -3455,26 +3456,33 @@ static char *handle_cross_project_links(cbm_mcp_server_t *srv, const char *args)
         const char *fcons = (const char *)sqlite3_column_text(stmt, MCP_COL_7);
         double conf = sqlite3_column_double(stmt, 8);
 
+        /* Grow buffer if needed (each entry is ~300 bytes max) */
+        if (pos + 512 > buf_cap) {
+            int new_cap = buf_cap * 2;
+            char *new_buf = realloc(buf, (size_t)new_cap);
+            if (!new_buf) break;  /* return what we have so far */
+            buf = new_buf;
+            buf_cap = new_cap;
+        }
+
         /* Protocol header */
         if (strcmp(cur_protocol, proto ? proto : "") != 0) {
             if (proto_count > 0) {
-                pos += snprintf(buf + pos, XL_BUF_SIZE - (size_t)pos, "\n");
+                pos += snprintf(buf + pos, (size_t)(buf_cap - pos), "\n");
             }
             snprintf(cur_protocol, sizeof(cur_protocol), "%s", proto ? proto : "");
-            pos += snprintf(buf + pos, XL_BUF_SIZE - (size_t)pos, "## %s\n\n", proto);
+            pos += snprintf(buf + pos, (size_t)(buf_cap - pos), "## %s\n\n", proto);
             proto_count++;
         }
 
-        pos += snprintf(buf + pos, XL_BUF_SIZE - (size_t)pos,
+        pos += snprintf(buf + pos, (size_t)(buf_cap - pos),
             "%s (confidence: %.2f)\n"
             "  producer: %s :: %s (%s)\n"
             "  consumer: %s :: %s (%s)\n\n",
             ident ? ident : "", conf,
             pprod ? pprod : "", qprod ? qprod : "", fprod ? fprod : "",
             pcons ? pcons : "", qcons ? qcons : "", fcons ? fcons : "");
         total++;
-
-        if (pos > 58000) break;  /* safety limit — leave headroom for header prepend */
     }
 
     sqlite3_finalize(stmt);
@@ -3486,13 +3494,14 @@ static char *handle_cross_project_links(cbm_mcp_server_t *srv, const char *args)
             "No cross-project links found. Index at least 2 projects first.", false);
     }
 
-    /* Prepend summary */
-    char header[128];
-    snprintf(header, sizeof(header), "# Cross-Project Links (%d total)\n\n", total);
-    int hlen = (int)strlen(header);
-    if (pos + hlen >= XL_BUF_SIZE) pos = XL_BUF_SIZE - hlen - 1;
-    memmove(buf + hlen, buf, (size_t)pos + 1);
+    /* Fill header in the reserved space, then shift content to close the gap */
+    char header[XL_HDR_RESERVE];
+    int hlen = snprintf(header, sizeof(header), "# Cross-Project Links (%d total)\n\n", total);
+    int gap = XL_HDR_RESERVE - hlen;
+    memmove(buf + hlen, buf + XL_HDR_RESERVE, (size_t)(pos - XL_HDR_RESERVE) + 1);
     memcpy(buf, header, (size_t)hlen);
+    pos -= gap;
+    buf[pos] = '\0';
 
     char *result = cbm_mcp_text_result(buf, false);
     free(buf);