Optimize and simplify loops, table lookups, and branchless parsers

- Replace sequential colon-counting loop with branchless CTZ bitmask in src/pen.h
- Replace linear strchr with 256-bit ASCII punctuation bitmask in src/selection.c
- Flatten 3D color cube loop and precompute constants in src/palette.c
- Use static 256-byte LUT for hex decoding and bsearch for termcap in src/escape.c
- Replace capacity doubling while loops with branchless CLZ pow2 helpers across core
- Use direct memset/memcpy in src/snapshot.c
- Optimize input digit/byte formatting, alt-prefix path, and make keyboard state optional in src/input.c

1 files changed, 2 insertions, 3 deletions

diff --git a/src/gstore.c b/src/gstore.c
index c5109c6..d2bc57f 100644
--- a/src/gstore.c
+++ b/src/gstore.c
@@ -355,9 +355,8 @@ uint32_t term_gstore_intern(struct gstore *g, const uint32_t *cps, int n)
     if (n > 2) {
         size_t extra = (size_t)(n - 2);
         if (g->arena_len + extra > g->arena_cap) {
-            size_t new_cap = g->arena_cap ? g->arena_cap * 2 : 512;
-            while (new_cap < g->arena_len + extra)
-                new_cap *= 2;
+            size_t new_cap = term_grow_cap(g->arena_cap ? g->arena_cap * 2 : 512,
+                                           g->arena_len + extra);
             uint32_t *next = realloc(g->arena, new_cap * sizeof(*next));
             if (!next) {
                 e->allocated = false;