chore: add 17 operational rules and rule index

- Create .claude/rules/ with all 17 standard rule files (01-security through 17-document-imports)
- Add Operational Rules section with Rule Index to .claude/CLAUDE.md

.claude/CLAUDE.md

@@ -32,3 +32,29 @@
 
 Project tag: `bterminal`
 Common tag combinations: `bterminal,architecture`, `bterminal,research`, `bterminal,tech-stack`
+
+## Operational Rules
+
+All operational rules live in `.claude/rules/`. Every `.md` file in that directory is automatically loaded at session start by Claude Code with the same priority as this file.
+
+### Rule Index
+
+| # | File | Scope |
+|---|------|-------|
+| 01 | `security.md` | **PARAMOUNT** — secrets, input validation, least privilege |
+| 02 | `error-handling.md` | **PARAMOUNT** — handle every error visibly |
+| 03 | `environment-safety.md` | **PARAMOUNT** — verify target, data safety, K8s isolation, cleanup |
+| 04 | `communication.md` | Stop on ambiguity, scope discipline |
+| 05 | `git-practices.md` | Conventional commits, authorship |
+| 06 | `testing.md` | TDD, unit tests, E2E tests |
+| 07 | `documentation.md` | README, CLAUDE.md sync, docs/ |
+| 08 | `branch-hygiene.md` | Branches, naming, clean state before refactors |
+| 09 | `dependency-discipline.md` | No deps without consent |
+| 10 | `code-consistency.md` | Match existing patterns |
+| 11 | `api-contracts.md` | Contract-first, flag breaking changes (path-conditional) |
+| 12 | `performance-awareness.md` | No N+1, no unbounded fetches (path-conditional) |
+| 13 | `logging-observability.md` | Structured logging, OTEL (path-conditional) |
+| 14 | `resilience-and-config.md` | Timeouts, circuit breakers, externalized config (path-conditional) |
+| 15 | `memora.md` | Persistent memory across sessions |
+| 16 | `sub-agents.md` | When to use sub-agents and team agents |
+| 17 | `document-imports.md` | Resolve @ imports in CLAUDE.md before acting |