Fix stale copy, dedupe Exit columns, document local report review

Follow-ups from review of the Track Record slim:

- BacktestPanel: drop the stale "tracking check" sentence from the "How this is
  measured" explainer — that check moved to the maintenance disclosure last
  commit, so it no longer describes anything in this block.
- MyTradesPanel: rename the two identically-labelled "Exit" columns to "Exit Px"
  (exit price) and "Reason" (close_reason) so they're not confusable.
- README: add "Reading a local backtest report" under Local Backtest Snapshots —
  a section->decision map for reports/backtest-*.json. The strategy-tuning tables
  removed from the deployed page (sweep, gate_ablation, time_exit_sweep,
  signal_eval, strategy_variants) now live only in the local report, so this
  keeps "research lives local" from meaning the decision knowledge evaporates.

tsc -b && vite build pass.

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

README.md

@@ -307,6 +307,28 @@ metrics. Keep the SSH tunnel open only while creating the snapshot; the backtest
 run itself is local/offline. `backtest_snapshots/` and generated backtest reports
 are git-ignored.
 
+### Reading a local backtest report
+
+The deployed **Signals → Track Record** page is deliberately trimmed to validation
+(portfolio monitor vs SPY, realized paper trades) and how-to-trade. The
+strategy-tuning tables that used to live there now live **only** in the local
+report — inspect these `reports/backtest-<timestamp>.json` sections and produce the
+matching decision. Every change still goes through the factor harness first (see
+**The iron rule for strategy changes** above).
+
+| Report section | What to read | Decision it drives |
+|---|---|---|
+| `overall_qualified` vs `overall_all` | Is qualified net expectancy above the all-setups baseline? | Sanity — is the gate adding anything at all |
+| `sweep` | Net avg R and trade count at each residual-momentum cutoff | Where to set the momentum percentile (Admin → Settings → Activation) |
+| `gate_ablation` | Net expectancy with each floor removed | Drop a floor only if removing it doesn't hurt net expectancy |
+| `time_exit_sweep` | Net avg R / net R-per-day by hold length | Whether a fixed time exit beats the promoted ATR trail |
+| `portfolio_monitor`, `portfolio_sim`, `strategy_variants` | CAGR, Sharpe, max drawdown, per-year returns | Promote a strategy only if it beats the current baseline on CAGR/Sharpe/DD |
+| `signal_eval` | Mean IC, t-stat, IC>0 %, `reliable` | Iron rule: wire a new factor in only if \|IC\| ≳ 0.03 with a consistent sign and `reliable: true` |
+| `recommendation`, `research_recommendation` | The report's own headline read | A starting point, not a substitute for the sections above |
+
+`recommendation` is the one section surfaced on the deployed page ("What this
+backtest recommends"); everything else in this table is intentionally local-only.
+
 ## Environment Variables
 
 Configure in `.env` (copy from `.env.example`):