Replace legacy scripts with separated ots/node hooks

- Remove deprecated scripts/ directory (6 files)
- Add hooks/post-commit-ots (ots CLI version)
- Add hooks/pre-commit-ots (ots CLI backfill)
- Add hooks/post-commit-node (Node.js version, local proofs only)
- Add hooks/pre-commit-node (Node.js backfill, no upgrade)
- Update hooks/install.sh to auto-detect and install matching hooks
- Update documentation (SKILL.md, README.md, AGENTS.md)
- Add node_modules/ to .gitignore for Node.js mode

Breaking change: Scripts removed, use new hooks/ directory.

README.md

@@ -13,14 +13,12 @@ Proofs are stored in `.ots/` and can be versioned alongside your code for tamper
 
 ## Quick Install
 
-### Recommended: Self-Contained Hooks
-
 ```bash
 # Clone or download this skill
 git clone <repository-url>
 cd git-ots-hook
 
-# Install both hooks (single command)
+# Install both hooks (auto-detects ots CLI or Node.js)
 ./hooks/install.sh /path/to/your/repo
 
 # Commit the proofs
@@ -31,31 +29,32 @@ git commit -m "Add OpenTimestamp proofs"
 
 That's it! The hooks are now installed and will automatically timestamp every commit.
 
-### Legacy: Script-Based Installation
-
-The older `scripts/` directory is still available but deprecated. See `SKILL.md` for details.
-
 ## Manual Installation
 
-If you prefer to install hooks manually without the installer:
-
-### 1. Copy Hook Files
+### For ots CLI (Recommended)
 
 ```bash
-cp hooks/post-commit /path/to/your/repo/.git/hooks/
-cp hooks/pre-commit /path/to/your/repo/.git/hooks/
-chmod +x /path/to/your/repo/.git/hooks/post-commit
-chmod +x /path/to/your/repo/.git/hooks/pre-commit
+cp hooks/post-commit-ots .git/hooks/post-commit
+cp hooks/pre-commit-ots .git/hooks/pre-commit
+chmod +x .git/hooks/post-commit .git/hooks/pre-commit
 ```
 
-### 2. Setup .gitignore
+### For Node.js (Local proofs only)
+
+```bash
+cp hooks/post-commit-node .git/hooks/post-commit
+cp hooks/pre-commit-node .git/hooks/pre-commit
+chmod +x .git/hooks/post-commit .git/hooks/pre-commit
+```
+
+### Setup .gitignore
 
-Add to your `.gitignore`:
 ```
 .ots/.attestation-cache
+node_modules/
 ```
 
-### 3. Commit Initial Proofs
+### Commit Initial Proofs
 
 ```bash
 git add .ots/