term: move the term core to subprojects/term

The core now builds, tests, and benchmarks alone, as a Meson subproject
with no dependency on the main tree.

- include/term/ holds term.h and the header-only unicode/. src/ holds
  the core and its private headers. The main tree gets only
  include/term through term_dep, so it cannot reach a private header.
- The term tests, the term benchmarks, the Kitty parser suite, and
  tools/amalgamate.py and tools/generate_unicode.py move with it. The
  tests run as term:<name>.
- The main build passes its -march (arch_flag) and b_ndebug to the
  subproject. A directory configured before this commit needs
  meson configure -Dterm:arch_flag=-march=... once.
- The term tests compile with -UNDEBUG. They do work inside assert.
- The subproject exports term_test_dep with term_api.h, for the main
  tree's render, thumbnail, color, and selection tests.
- The Kitty bridge used struct vector2i and has not compiled since the
  public API redesign. It builds again. 2 of its 14 tests fail: REP
  after a tab, and a cursor report after a resize.
- dirgraph.py drops the term and unicode layers. Its self-test uses pty.
- The symbols test ignores the __odr_asan symbols that ASan adds.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 34 insertions, 0 deletions

diff --git a/src/palette.h b/src/palette.h
new file mode 100644
index 0000000..5eef03e
--- /dev/null
+++ b/src/palette.h
@@ -0,0 +1,34 @@
+#ifndef TERM_PALETTE_H
+#define TERM_PALETTE_H
+
+#include <stdbool.h>
+#include <stdint.h>
+
+#include "term.h"
+
+/*
+ * The colors of one terminal. base holds the colors that the theme gives;
+ * colors holds base plus the entries that the program changed with OSC 4,
+ * 10, 11, or 12. version changes whenever colors changes.
+ */
+struct palette {
+    uint32_t colors[TERM_PALETTE_SIZE];
+    uint32_t base[TERM_PALETTE_SIZE];
+    struct term_theme theme;
+    uint64_t version;
+};
+
+/* Set every entry from theme. An all-zero theme selects the built-in theme. */
+void term_palette_init(struct palette *p, const struct term_theme *theme);
+/* Change one entry (0-255, TERM_PALETTE_FG, _BG, or _CURSOR). */
+void term_palette_set(struct palette *p, int slot, uint32_t argb);
+/* Restore one entry, or all entries, to the theme color. */
+void term_palette_reset(struct palette *p, int slot);
+void term_palette_reset_all(struct palette *p);
+
+static inline uint32_t palette_resolve(const struct palette *p, term_color c)
+{
+    return term_color_is_slot(c) ? p->colors[c & 0x1FFu] : c;
+}
+
+#endif