Add T0.95 late-order heat stage

Request:
- Reflect that near-final market heat can be used when the user can still place an IPO order at T0.95.

Changes:
- Added T0_95_final_heat as a separate analyst decision stage with executability and no-leakage rules.
- Added an experimental T0.95 rule overlay for late-order heat scoring and calibration discipline.
- Updated archivist guidance and the market-heat archiver so snapshots can be explicitly stored as T0_95_final_heat.
- Added market_heat_stage to the analysis dataset and refreshed the model report to show T0.95 coverage separately.

Verification:
- Ran py_compile for the modified scripts.
- Checked archive_t0_5_market_heat.py --help for the new --stage option.
- Rebuilt data/snapshots/analysis_model_v0_dataset.csv and reports/2026-06-15_analysis_model_v0.md.
- Ran git diff --check.

Next useful context:
- Current archived heat rows remain T0_5_market_heat only; there are no true T0.95 rows yet.
- external_ipo_history.public_oversubscription_times is still calibration-only unless a comparable value is archived before the executable order cutoff.

rules/rule_change_log.md

@@ -1,5 +1,28 @@
 # Rule Change Log
 
+## 2026-06-15 - Add T0.95 late-order heat stage
+
+Request:
+
+- Treat near-deadline heat as usable when the user can still place an IPO order at T0.95.
+
+Change:
+
+- Added `T0_95_final_heat` to the analyst skill as a separate actionable late-order stage.
+- Added `rules/ipo_score_v0_95_final_heat_trial.yaml` for stage-safe T0.95 heat scoring and timing discipline.
+- Updated the archivist skill and `scripts/archive_t0_5_market_heat.py` so market-heat snapshots can be explicitly archived as `T0_95_final_heat`.
+
+Rationale:
+
+- If the user can still place, amend, or cancel an order near the subscription cutoff, near-final heat is a legitimate live decision input.
+- Historical final public oversubscription can help calibrate near-final heat buckets, but it remains post-hoc calibration unless the value was visible before the user's executable order cutoff.
+
+Verification:
+
+- Kept the script default stage as `T0_5_market_heat` for backward compatibility.
+- Added explicit `--stage T0_95_final_heat` support for late-order snapshots.
+- Verified with py_compile, script help output, dataset rebuild, and `git diff --check`.
+
 ## 2026-06-15 - Use Chinese for analyst reports
 
 Request: