Increment 0: add XCTest target, testing process & 10x value plan

- Add TopManagerTests unit-test target (hosted, @testable import)
- 14 baseline tests for formatters and model math (all green)
- scripts/test.sh build+test loop driver
- docs/TESTING.md (5-gate process), docs/VALUE_PLAN.md (10x rubric)

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

docs/TESTING.md

@@ -0,0 +1,67 @@
+# TopManager — Testing Process
+
+This document defines the repeatable test process used while evolving TopManager.
+Every feature increment must pass all five gates below before it is considered done.
+
+## Gate 1 — Compile
+```bash
+scripts/test.sh build
+```
+Fast feedback that the code compiles for `platform=macOS,arch=arm64`. First gate on every change.
+
+## Gate 2 — Unit tests (automated, self-run)
+```bash
+scripts/test.sh test        # or: xcodebuild ... test
+```
+Pure-logic is covered by XCTest in `TopManagerTests/` using `@testable import TopManager`.
+The suite intentionally targets deterministic logic (no live system state):
+
+- **Formatting / model math** — bytes, rates, percentages, uptime, usage %.
+- **MetricsStore** — ring-buffer trim, persistence round-trip, downsampling per range.
+- **Energy heuristic** — score is monotonic in CPU and wakeups, clamped to 0–100.
+- **Alert engine** — threshold crossings fire/clear correctly, sustained-window logic,
+  de-duplication (no alert storms), severity ordering.
+- **Health score** — 0–100, decreases with pressure/thermal/swap/disk load.
+- **Battery math** — time-remaining and capacity-health formatting.
+
+Tests must stay hermetic: no sleeping on real timers, no asserting on live CPU numbers.
+
+## Gate 3 — Runtime smoke test (self-run on this machine)
+Launch the built app, drive real load, confirm no crash and data populates.
+```bash
+# build a runnable .app
+xcodebuild -project TopManager.xcodeproj -scheme TopManager -configuration Debug \
+  -destination 'platform=macOS,arch=arm64' build CODE_SIGNING_ALLOWED=NO
+APP=$(find ~/Library/Developer/Xcode/DerivedData/TopManager-*/Build/Products/Debug -name TopManager.app | head -1)
+open "$APP"
+# generate CPU load in the background, then verify TopManager surfaces it
+yes > /dev/null & LOAD=$!; sleep 8; kill $LOAD
+```
+Verify: process list shows the load generator near the top, charts move, no crash in
+`Console`/stderr, menu bar updates, alerts fire when thresholds are crossed.
+
+## Gate 4 — Ground-truth cross-checks
+TopManager's numbers are validated against OS tools so we don't ship wrong data:
+
+| TopManager metric      | Ground truth command                        |
+|------------------------|---------------------------------------------|
+| Per-process CPU/mem    | `ps -Ao pid,pcpu,pmem,comm -r | head`       |
+| System memory          | `vm_stat`, `sysctl vm.swapusage`            |
+| Disk volumes / free    | `df -h`                                      |
+| Battery / power        | `pmset -g batt`, `ioreg -rn AppleSmartBattery` |
+| Thermal state          | `pmset -g therm`                             |
+| Network throughput     | `netstat -ib`                                |
+
+Small deltas are expected (sampling windows differ); order-of-magnitude or ranking
+mismatches are bugs.
+
+## Gate 5 — Regression: original features intact
+Manually confirm each shipped feature still works: Processes (sort/search/kill/suspend/
+resume), Apps (activate/hide/quit/force-quit/copy bundle id), Performance (CPU/Mem/Net
+charts), Power & Storage (system/GPU/storage/network), and the menu-bar readout.
+
+## Loop
+```
+implement slice → Gate 1 → Gate 2 → Gate 3 → Gate 4 → Gate 5 → checkpoint commit
+```
+Repeat per increment until the value rubric in `docs/VALUE_PLAN.md` is met.