feat(spells): honor spell cast time in the action budget

SpellSpec gains a cast_time field (seven budget codes; the JSON loader
also accepts RAW phrasings like "1 round" or "1 minute"). The pure
budget filters take a CastTimeResolver so a cast_spell occupies the slot
its casting time maps to: standard->standard, swift->swift (competing
with deed/inspire courage and dropped by a consumed immediate),
immediate/free->free, full_round and one_round->full_round (one_round
clamped: resolved end-of-turn, documented approximation), long->dropped
before the budget filter with the new downgraded:cast_time reason. The
engine binds its registry lookup via _cast_time_of (unknown names fall
back to standard, keeping transcripts byte-identical);
_choose_spell_action never selects long casts; the staggered filter now
drops full-round casts and spell_combat via the effective slot
(_FULL_ROUND_KINDS becomes dead and is deleted). Summon Monster I/II are
the only data spells marked 1 round. Metamagic full-round casting for
spontaneous casters is out of scope (future hook documented in
_cast_time_of).

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

data/spells/summon_monster_ii.json

@@ -5,6 +5,7 @@
   "range": "close",
   "save": "none",
   "base_dc": 10,
+  "cast_time": "1 round",
   "effects": [
     {
       "type": "summon",