Fix pre-existing issues and update README for v2.0

- Fix _infer_state_from_artifacts: SPEC-only maps to research (was bug_find)
- Fix cmd_validate_folder: corrupted .state files now error instead of silent fallback
- Fix upgrade.sh: remove || true, add python3 check, use git rev-parse --git-dir
- Update README.md with --project flag, --can-edit modes, --upgrade, enforcement layers
- Add 6 new tests for inference and validation fixes
- Complete hook-install-process and readme-upgrade-docs tasks

tasks/hook-install-process/ADVERSARIAL_BUG_REPORT.md

@@ -0,0 +1,21 @@
+# Adversarial Bug Report: hook-install-process
+
+## Summary
+No critical issues. Two minor observations.
+
+## Bugs Found
+
+### Bug 1: upgrade.sh doesn't verify python3 is available (Low)
+- **Severity**: Low
+- **Location**: scripts/upgrade.sh line 26
+- **Description**: The script runs `python3 "$STATUS_SCRIPT" --upgrade` without checking if python3 exists. If python3 is not on PATH, the upgrade silently fails (due to `|| true`).
+- **Suggested Fix**: Add a python3 availability check at the start.
+
+### Bug 2: Pre-commit hook doesn't handle bare repos (Low)
+- **Severity**: Low
+- **Location**: scripts/git-hooks/pre-commit
+- **Description**: If the project uses a bare repo or worktrees, `.git/hooks/` may not exist at the expected path.
+- **Suggested Fix**: Use `git rev-parse --git-dir` instead of assuming `.git/hooks/`.
+
+## Score
++5