feat(02-05): sim/offline + auto-harvest + letter Ink + letter-renderer

- src/sim/offline/: OfflineEventBlockSchema (Zod) + EMPTY_OFFLINE_EVENTS
  + aggregateOfflineEvent pure aggregator (D-19); 14 tests green
- src/sim/garden/auto-harvest.ts: autoHarvestReadyPlants silent-mode
  branch (D-10); reuses harvest() pipeline so selector + Pitfall 10
  unlocks + STRY-10 Lura gate all run identically; BLOCKER 3 invariant
  preserved (no lastTickAt writes); 7 tests green
- simulateOneTick: ctx.silent triggers auto-harvest sweep before tick
  increment; active-play path unchanged (silent defaults false)
- content/dialogue/season1/letter-from-the-garden.ink: authored skeleton
  with VAR plants_bloomed / fragment_titles / lura_was_here per D-17/D-18;
  bible voice, anti-FOMO compliant, 24h cap silent in voice (D-11)
- ink-loader: loadInkStory union extended with letter-from-the-garden;
  separate letterStoryGlob for lazy code-split chunk; INK_VARIABLE_MAP
  gains plants_bloomed / fragment_titles / lura_was_here slots reading
  from session.pendingLetterEventBlock
- src/ui/letter/letter-renderer.ts: pure buildLetterSlots helper —
  prefers fragment first-sentence body for tonal weight, slugified-id
  fallback; 10 tests green
- npm run compile:ink emits 5 .ink.json files (was 4); Vite emits the
  letter as a separate lazy chunk (letter-from-the-garden.ink-*.js)
- 295/295 tests green (was 264; +31 new); npm run ci exits 0

content/dialogue/season1/letter-from-the-garden.ink

@@ -0,0 +1,47 @@
+// Letter from the garden — UX-02 + CONTEXT D-17 + D-18 + D-20.
+//
+// Composed from authored skeleton + templated insertions per CONTEXT D-17.
+// Slots populated at runtime from sim/offline/events.ts via the variable
+// map in src/content/ink-loader.ts.
+//
+// Per Pitfall 4: Ink VAR names are snake_case AND case-sensitive.
+// Per CONTEXT D-11: 24h offline cap is silent in voice — no numeric
+// "28h" copy in any branch.
+// Per CLAUDE.md Tone — the gardener-keeper voice. Warm. Specific.
+// Intermittent. Sometimes funny, sometimes devastating. Never a stat
+// dump (UX-02 explicitly forbids that). The skeleton holds the voice;
+// the slots fill in the specifics.
+// Per anti-fomo-doctrine.md: this letter is NOT a "you missed X — come
+// back tomorrow!" nag. It is a contemplative summary of what stayed.
+
+VAR plants_bloomed = 0
+VAR fragment_titles = ""
+VAR lura_was_here = false
+VAR fragment_count = 0
+VAR last_plant_type = ""
+
+== letter ==
+
+The garden held its breath while you were gone.
+
+{ plants_bloomed > 1:
+    {plants_bloomed} blooms came and went, each leaving the soil a little quieter than they found it.
+- else:
+  { plants_bloomed == 1:
+      One bloom came and went. The space it left feels generous, somehow.
+  - else:
+      Nothing bloomed. The wind carried something else, and the garden held that, too.
+  }
+}
+
+{ fragment_titles != "":
+    Among what stayed: {fragment_titles}.
+}
+
+{ lura_was_here:
+    Lura came by once. She did not knock. She left a folded leaf on the gate post — you'll find it when you next walk past.
+}
+
+The light is the same as when you left. The garden is older.
+
+-> END