Add the Corporate Ladder pack, and two engine features it needed

Seventeen events across the mailroom: ordinary days, Marlene Hobb and Trevor
Pike, a misrouted envelope that can be delivered or kept, and a hard-times
branch that fires on negative money and always leaves an ungated way out.

Writing real content turned up two things the engine could not express.

Per-turn upkeep (`pack.upkeep`): the MVP spec wants recurring income and costs,
but effects only run when a player chooses something, and baking wages into
every option would be tedious and easy to get wrong. Upkeep entries carry their
own conditions, which turned out to be enough for the loan service charge to be
a three-step function that escalates with the size of the debt — no multiply
operation, no engine change. Upkeep changes are recorded separately from choice
changes so the UI can distinguish them.

Per-character starting relationships: Trevor starts below the pack default on
`likes_you` because he arrived two weeks earlier and has priced that in.
Characterisation as data rather than as an opening cutscene. Nobody starts
feared, either — `fears_you` defaults to 10, since a midpoint default would mean
every new hire arrives already intimidating.

The content suite plays 60 seeded runs and asserts every event fires and every
option is taken at least once. That caught real dead content: Trevor's favour
chain sat behind a gate no plausible player could reach, taking two events and a
hard-times escape route with it, and debt could pass 5,500 while the service
charge stayed flat, so the failure spiral flattened out instead of tightening.
Both fixed in the data — the gate softened and given another route up, the loan
capped and its charge tiered.

The validator also gained a real fix: it counted an event with a cooldown as a
stage's fallback, but a cooldown can exclude it, so a stage could still run dry.

86 tests. Reasoning in docs/DECISIONS.md §11-13, including the seeding trap that
makes a correlated chooser look exactly like a content bug.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VMSFHyVPitUoosW5wyEADj

src/engine/game.js

@@ -7,6 +7,7 @@
 
 import { createRng } from './rng.js';
 import { applyEffects } from './effects.js';
+import { check } from './conditions.js';
 import { resolveSchema, createState } from './state.js';
 import { selectEvent, resolveOptions, findOption } from './select.js';
 import { setPath, getPath } from './paths.js';
@@ -29,6 +30,24 @@ function advance(pack, state) {
   return next;
 }
 
+/**
+ * Apply the pack's per-turn upkeep — wages in, rent out, whatever a loan
+ * costs to carry. Each entry may carry its own conditions, evaluated after the
+ * player's choice has landed, so upkeep is content's business and not a
+ * special case in the loop.
+ */
+function applyUpkeep(pack, state, schema) {
+  let next = state;
+  const changes = [];
+  for (const entry of pack.upkeep ?? []) {
+    if (!check(next, entry.requires).passed) continue;
+    const applied = applyEffects(next, entry.effects, schema);
+    next = applied.state;
+    changes.push(...applied.changes.map((change) => ({ ...change, label: entry.label ?? null })));
+  }
+  return { state: next, changes };
+}
+
 /** Begin a run. `seed` is any string or number; it is stored in the save. */
 export function startGame(pack, { seed = Date.now(), schema = resolveSchema(pack), now = null } = {}) {
   let state = createState(pack, { seed, schema });
@@ -73,6 +92,9 @@ export function takeTurn(pack, state, optionId, { schema = resolveSchema(pack),
   next = setPath(next, `seen.${event.id}`, seenCount + 1);
   next = setPath(next, `lastSeen.${event.id}`, next.turn);
 
+  const upkeep = applyUpkeep(pack, next, schema);
+  next = upkeep.state;
+
   const record = {
     turn: next.turn,
     stage: next.stage,
@@ -80,6 +102,7 @@ export function takeTurn(pack, state, optionId, { schema = resolveSchema(pack),
     optionId: option.id,
     optionLabel: option.label,
     changes: applied.changes,
+    upkeep: upkeep.changes,
     offered: resolved.map((r) => ({
       id: r.option.id,
       label: r.option.label,

src/engine/state.js

@@ -27,7 +27,11 @@ export function resolveSchema(pack) {
   }
   for (const character of pack.characters ?? []) {
     for (const [stat, rule] of Object.entries(pack.relationshipStats ?? {})) {
-      schema[`relationships.${character.id}.${stat}`] = { ...rule };
+      // A character may start somewhere other than the pack default — a rival
+      // who already resents you, a boss who has not formed an opinion.
+      const override = character.startingRelationship?.[stat];
+      schema[`relationships.${character.id}.${stat}`] =
+        override === undefined ? { ...rule } : { ...rule, initial: override };
     }
   }
   return schema;

src/engine/validate.js

@@ -95,6 +95,29 @@ export function validatePack(pack) {
     list.forEach(walk);
   };
 
+  (pack.upkeep ?? []).forEach((entry, index) => {
+    const where = `upkeep[${index}]${entry.label ? ` "${entry.label}"` : ''}`;
+    checkConditions(where, entry.requires);
+    if (!entry.effects?.length) fail(where, 'has no effects');
+    for (const effect of entry.effects ?? []) {
+      if (!OPERATIONS.includes(effect.op)) {
+        fail(where, `unknown effect operation ${JSON.stringify(effect.op)}`);
+      }
+    }
+    for (const path of effectPaths(entry.effects)) {
+      const problem = writable(path);
+      if (problem) fail(where, `effect writes ${problem}`);
+    }
+  });
+
+  for (const character of pack.characters ?? []) {
+    for (const stat of Object.keys(character.startingRelationship ?? {})) {
+      if (!(stat in (pack.relationshipStats ?? {}))) {
+        fail(`character "${character.id}"`, `startingRelationship names unknown stat "${stat}"`);
+      }
+    }
+  }
+
   const stages = new Set();
   const unconditional = new Set();
   const seenEvents = new Set();