Add merit node type (Scene 8 ceremony + achievement award)

A merit node awards a configured achievement (awards_flag) to the player
the moment the playthrough arrives on it, with node provenance, then
presents a ceremony. Migration 028 extends node_type + the component_key
CHECK and adds awards_flag; the runtime grants the flag in advance/goto/
new-game write paths; MeritHost renders the ceremony (a component_key can
supply a bespoke one, e.g. a 3D model). Verified: teleport to a merit node
auto-grants its achievement.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/styles.css

@@ -520,6 +520,9 @@ button:focus-visible { outline: 2px solid #e99a44; outline-offset: 2px; }
 
 /* Story-graph runtime: cutscene title card + report-back */
 .cutscene-card { position: fixed; inset: 0; z-index: 200; display: grid; place-items: center; background: #04110e; cursor: pointer; animation: dialogue-in .3s ease; }
+.merit-card { background: radial-gradient(120% 90% at 50% 35%, #16240f 0%, #0a1408 60%, #04110e 100%); }
+.merit-card .merit-eyebrow { color: #cdea6a; }
+.merit-flag { font: 13px IBM Plex Mono; letter-spacing: .12em; color: #d58a46; margin: 0; }
 .title-card-inner { display: grid; justify-items: center; text-align: center; gap: 18px; animation: title-rise 1.1s cubic-bezier(.2,.7,.2,1); }
 @keyframes title-rise { from { opacity: 0; transform: translateY(14px); } to { opacity: 1; transform: none; } }
 .title-card-inner small { font: 10px IBM Plex Mono; letter-spacing: .3em; color: #7f9a92; text-transform: uppercase; }