fix: Hook scripts don't follow #!/usr/bin/env bash convention from AGENTS.md (#330)

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

lib/hooks/on-compact-reinject.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 # on-compact-reinject.sh — SessionStart (compact) hook for dark-factory agent sessions.
 #
 # Called by Claude Code after context compaction. Reads a context file and

lib/hooks/on-idle-stop.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 # on-idle-stop.sh — Stop hook for dark-factory agent sessions.
 #
 # Called by Claude Code when it finishes a response. Writes a timestamp

lib/hooks/on-phase-change.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 # on-phase-change.sh — PostToolUse hook for phase file write detection.
 #
 # Called by Claude Code after every Bash|Write tool execution.

lib/hooks/on-pretooluse-guard.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 # on-pretooluse-guard.sh — PreToolUse hook: guard destructive operations.
 #
 # Called by Claude Code before executing a Bash command in agent sessions.

lib/hooks/on-session-end.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 # on-session-end.sh — SessionEnd hook for dark-factory agent sessions.
 #
 # Called by Claude Code when a session terminates (clean exit, logout,

lib/hooks/on-stop-failure.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 # on-stop-failure.sh — StopFailure hook for immediate phase file update on API error.
 #
 # Called by Claude Code when a turn ends due to an API error (rate limit,

lib/hooks/on-stop-matrix.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 # on-stop-matrix.sh — Stop hook: post Claude response to Matrix thread.
 #
 # Called by Claude Code after each assistant turn. Reads the response from