feat: add apotheosis third prestige layer and remove IDEAS.md

Apotheosis is the ultimate reset — wipes absolutely everything
including prestige and transcendence — in exchange for a pure
bragging-rights badge. No mechanical benefit whatsoever.

Unlock condition: all 15 Transcendence echo upgrades purchased.
Can be achieved multiple times; each cycle requires repurchasing
all Transcendence upgrades again.

What survives: Codex lore entries and lifetime profile statistics.
What is wiped: resources, prestige, runestones, transcendence data
(echoes, echo upgrades, multipliers), equipment, upgrades, bosses,
quests, zones, adventurers, achievements.

New files: Apotheosis.ts type, apotheosis service, apotheosis route,
ApotheosisPanel.tsx component.

Modified: GameState (apotheosis field), Api.ts, types/index.ts,
prestige service (carry apotheosis), transcendence service (carry
apotheosis), game.ts anti-cheat (cap apotheosis count), API client,
GameContext (apotheosis() function), GameLayout (new tab), ResourceBar
(gold apotheosis badge shown above transcendence and prestige badges),
styles.css, AboutPanel how-to-play.

Also removes IDEAS.md — all planned features are now implemented!

apps/web/src/styles.css

@@ -2441,3 +2441,84 @@ body {
   cursor: not-allowed;
   opacity: 0.4;
 }
+
+/* ── Apotheosis ─────────────────────────────────────────────────────────── */
+
+.apotheosis-badge {
+  background: linear-gradient(135deg, #78350f, #d97706, #fbbf24);
+  border-radius: 999px;
+  color: #1c1917;
+  font-size: 0.85rem;
+  font-weight: 700;
+  padding: 0.25rem 0.75rem;
+}
+
+.apotheosis-panel .apotheosis-intro {
+  color: var(--colour-text-muted);
+  font-size: 0.95rem;
+  margin-bottom: 0.75rem;
+}
+
+.apotheosis-reward {
+  background: linear-gradient(135deg, rgba(120, 53, 15, 0.2), rgba(217, 119, 6, 0.2));
+  border: 1px solid #d97706;
+  border-radius: var(--radius);
+  font-size: 1rem;
+  margin: 1rem 0;
+  padding: 0.75rem 1rem;
+  text-align: center;
+}
+
+.apotheosis-count {
+  background: var(--colour-surface);
+  border: 1px solid #d97706;
+  border-radius: var(--radius);
+  margin: 0.75rem 0;
+  padding: 0.75rem 1rem;
+  text-align: center;
+}
+
+.apotheosis-status {
+  background: var(--colour-surface);
+  border: 1px solid #d97706;
+  border-radius: var(--radius);
+  margin: 1rem 0;
+  padding: 1rem;
+}
+
+.apotheosis-status p {
+  margin: 0.25rem 0;
+}
+
+.apotheosis-missing {
+  color: var(--colour-text-muted);
+  font-size: 0.9rem;
+}
+
+.apotheosis-ready {
+  color: #fbbf24;
+  font-weight: 600;
+}
+
+.apotheosis-button {
+  background: linear-gradient(135deg, #78350f, #d97706);
+  border: none;
+  border-radius: var(--radius);
+  color: #fff;
+  cursor: pointer;
+  font-size: 1rem;
+  font-weight: 700;
+  margin-top: 0.5rem;
+  padding: 0.75rem 2rem;
+  transition: opacity 0.2s;
+  width: 100%;
+}
+
+.apotheosis-button:hover:not(:disabled) {
+  opacity: 0.85;
+}
+
+.apotheosis-button:disabled {
+  cursor: not-allowed;
+  opacity: 0.4;
+}