chore: add Claude Code ruleset via ~/code/rulesets install-elisp

Installs the Elisp ruleset from the rulesets repo:

  - CLAUDE.md (project instructions template)
  - .claude/rules/ (testing, verification, elisp, elisp-testing)
  - .claude/hooks/validate-el.sh (check-parens + byte-compile + run
    matching tests on every .el edit via PostToolUse)
  - .claude/settings.json (permission allowlist + hook wiring)
  - githooks/pre-commit (secret scan + staged-file paren check)

core.hooksPath set to githooks/ so the pre-commit activates automatically.
Hooks use \$CLAUDE_PROJECT_DIR with a script-relative fallback, so a
fresh clone works without path edits.

.gitignore extended with personal-override entries (settings.local.json,
.cache/) and byte-compile artifacts (*.elc, *.eln).

1 files changed, 66 insertions, 0 deletions

diff --git a/CLAUDE.md b/CLAUDE.md
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+# CLAUDE.md
+
+## Project
+
+Elisp project. Customize this section with your own description, layout, and conventions.
+
+**Typical layout:**
+- `init.el`, `early-init.el` — entry points (Emacs config projects)
+- `modules/*.el` — feature modules
+- `tests/test-*.el` — ERT unit tests
+- `tests/testutil-*.el` — shared test fixtures and mocks
+
+## Build & Test Commands
+
+If the project has a Makefile, document targets here. Common pattern:
+
+```bash
+make test                               # All tests
+make test-file FILE=tests/test-foo.el   # One file
+make test-name TEST=pattern             # Match test names
+make validate-parens                    # Balanced parens in modules
+make validate-modules                   # Load all modules to verify they compile
+make compile                            # Byte-compile (writes .elc)
+make lint                               # checkdoc + package-lint + elisp-lint
+```
+
+Alternative build tools: `eldev`, `cask`, or direct `emacs --batch` invocations.
+
+## Language Rules
+
+See rule files in `.claude/rules/`:
+- `elisp.md` — code style and patterns
+- `elisp-testing.md` — ERT conventions
+- `verification.md` — verify-before-claim-done discipline
+
+## Git Workflow
+
+- Conventional commit prefixes: `feat:`, `fix:`, `refactor:`, `test:`, `docs:`, `chore:`
+- Pre-commit hook in `githooks/` scans for secrets and runs `check-parens` on staged `.el` files
+- Activate on fresh clone: `git config core.hooksPath githooks`
+
+## Problem-Solving Approach
+
+Investigate before fixing. When diagnosing a bug:
+1. Read the relevant module and trace what actually happens
+2. Identify the root cause, not a surface symptom
+3. Write a failing test that captures the correct behavior
+4. Fix, then re-run tests
+
+## Testing Discipline
+
+TDD is the default: write a failing test before any implementation. If you can't write the test, you don't yet understand the change. Details in `.claude/rules/elisp-testing.md`.
+
+## Editing Discipline
+
+A PostToolUse hook runs `check-parens` + `byte-compile-file` on every `.el` file after Edit/Write/MultiEdit. Byte-compile warnings (free variables, wrong argument counts) are signal — read them.
+
+Prefer Write over cumulative Edits for nontrivial new code. Small functions (under 15 lines) are near-impossible to get wrong; deeply nested code is where paren errors hide.
+
+## What Not to Do
+
+- Don't add features beyond what was asked
+- Don't refactor surrounding code when fixing a bug
+- Don't add comments to code you didn't change
+- Don't create abstractions for one-time operations
+- Don't commit `.env` files, credentials, or API keys — pre-commit hook catches common patterns but isn't a substitute for care