tools: add repl-block, check-tangle; move existing tools into memex

New tools (projects/<tool>/ — standalone, git-committed):
- repl-block: extract and pipe lisp blocks from org files to the REPL
- check-tangle: tangle + compile in one step, reports errors

Existing tools moved from ~/.opencode/bin/ into memex (survives reinstalls):
- repl, tangle, org-eval, verify-repl

AGENTS.md updated:
- Tool reference table with all 7 tools
- Package reference table for passepartout and cl-tty
- Updated tangle command to use project-local tools

.opencode/commands/ added: check-parens, repl-block, check-tangle commands

projects/tangle-tool/tangle

@@ -0,0 +1,27 @@
+#!/usr/bin/env bash
+# Tangle an org file using Emacs batch mode
+# Usage: tangle <org-file>
+
+set -e
+
+if [ $# -ne 1 ]; then
+    echo "Usage: tangle <org-file>"
+    echo "  Tangles all src blocks with :tangle directives to their targets"
+    exit 1
+fi
+
+ORG_FILE="$1"
+
+if [ ! -f "$ORG_FILE" ]; then
+    echo "Error: File not found: $ORG_FILE"
+    exit 1
+fi
+
+echo "Tangling: $ORG_FILE"
+
+emacs --batch \
+    --load org \
+    --eval "(setq org-confirm-babel-evaluate nil)" \
+    --eval "(org-babel-tangle-file \"$ORG_FILE\")"
+
+echo "Done."