fix: respect user timeouts on low-memory systems (#1221)

Closes #1219

## Problem

On 8GB RAM machines, renders time out at 5% with `Runtime.callFunctionOn timed out` during the duration probe. User-set timeout env vars (`PRODUCER_PUPPETEER_PROTOCOL_TIMEOUT_MS`) are silently ignored by the calibration path, and there are no CLI flags to control timeouts directly.

## Root causes

1. **Calibration timeout cap overrides user settings** — `createCaptureCalibrationConfig` used `Math.min(cfg.protocolTimeout, 30_000)`, meaning even if the user set 300s, calibration still capped at 30s. On slow hardware this causes unnecessary timeouts.

2. **8GB systems get no low-memory treatment** — `getLowMemoryFlags()`, `getGpuMemBudgetMb()`, `memoryAdaptiveCacheLimit()`, and `memoryAdaptiveCacheBytesMb()` all used `< 8192` as the threshold. Systems reporting exactly 8192 MB (common for 8GB machines) fell through to the "plenty of memory" path, getting no Chrome heap reduction or cache limits.

3. **No CLI flags for key timeouts** — Users had to discover the correct env var names (`PRODUCER_PUPPETEER_PROTOCOL_TIMEOUT_MS`, `PRODUCER_PLAYER_READY_TIMEOUT_MS`) by reading source. The non-existent `PUPPETEER_PROTOCOL_TIMEOUT` and `--browser-timeout` were common guesses that did nothing.

## Changes

- `captureCost.ts`: `Math.min` → `Math.max` so the 30s calibration default is a floor, not a ceiling. User-set higher timeouts are now respected.
- `browserManager.ts`: `>= 8192` → `> 8192` in `getLowMemoryFlags()` and `<= 8192` in `getGpuMemBudgetMb()` so 8GB systems get reduced Chrome heap and GPU memory budget.
- `config.ts`: `< 8192` → `<= 8192` in `memoryAdaptiveCacheLimit()` and `memoryAdaptiveCacheBytesMb()` so 8GB systems get reduced frame cache limits.
- `render.ts`: Added `--protocol-timeout <ms>` and `--player-ready-timeout <ms>` CLI flags, wired through `resolveConfig` overrides.
- Updated calibration tests to match the new floor-not-ceiling behavior.
- Added fallow suppressions for pre-existing unused exports in `captureCost.ts`.

## Test plan

- [x] Engine config tests pass (`vitest run src/config.test.ts`)
- [x] Browser manager tests pass (`vitest run src/services/browserManager.test.ts`)
- [x] Calibration safeguard tests pass (4/4 in `renderOrchestrator.test.ts`)
- [x] TypeScript compiles cleanly for engine and cli packages
- [ ] CI pipeline

packages/studio/src/player/components/Timeline.test.ts

@@ -230,7 +230,8 @@ describe("getTimelinePlayheadLeft", () => {
 
 describe("getTimelineCanvasHeight", () => {
   it("includes bottom scroll buffer below the last track", () => {
-    expect(getTimelineCanvasHeight(3)).toBeGreaterThan(24 + 3 * 72);
+    // RULER_H (24) + trackCount * TRACK_H (48) + scroll buffer
+    expect(getTimelineCanvasHeight(3)).toBeGreaterThan(24 + 3 * 48);
   });
 
   it("still keeps ruler space when there are no tracks", () => {