feat: add MEMPAL_VERBOSE toggle — developers see diaries in chat (#871)

export MEMPAL_VERBOSE=true  → hook blocks, agent writes diary in chat
export MEMPAL_VERBOSE=false → silent background save (default)

Developers need to see code and diaries being written.
Regular users want zero chat clutter. Now both work.

TDD: tests written first, failed, code fixed, tests pass.

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/test_save_hook_verbose.py

@@ -0,0 +1,44 @@
+"""TDD: save hook must support verbose mode for developers.
+
+Developers want to see diaries and code in chat.
+Regular users want silent background saves.
+The hook should check a config flag.
+"""
+
+import os
+
+
+class TestSaveHookVerboseMode:
+    """Save hook must have a verbose/silent toggle."""
+
+    def test_hook_checks_verbose_flag(self):
+        """Hook must read a MEMPAL_VERBOSE or similar flag."""
+        hook_path = os.path.join(
+            os.path.dirname(os.path.dirname(__file__)),
+            "hooks",
+            "mempal_save_hook.sh",
+        )
+        src = open(hook_path).read()
+        has_verbose = "VERBOSE" in src or "verbose" in src or "SILENT" in src or "silent" in src
+        assert has_verbose, (
+            "Save hook has no verbose/silent toggle. "
+            "Developers need to see diaries and code in chat. "
+            "Add MEMPAL_VERBOSE flag: when true, hook blocks and asks "
+            "agent to write; when false, saves silently."
+        )
+
+    def test_verbose_mode_blocks(self):
+        """When verbose, hook should use decision: block so agent writes in chat."""
+        hook_path = os.path.join(
+            os.path.dirname(os.path.dirname(__file__)),
+            "hooks",
+            "mempal_save_hook.sh",
+        )
+        src = open(hook_path).read()
+        # There should be TWO decision paths: block (verbose) and allow (silent)
+        has_block = '"decision": "block"' in src or "'decision': 'block'" in src
+        has_allow = '"decision": "allow"' in src or "'decision': 'allow'" in src
+        assert has_block and has_allow, (
+            "Hook needs both 'block' (verbose/developer) and 'allow' (silent) paths. "
+            f"Has block: {has_block}, has allow: {has_allow}"
+        )