feat: wizard remediation — password mask, hooks preview, headless (IUH-M02)

Implements three wizard UX gaps identified in issue #426:

AC-3: Replace plaintext password prompt in bootstrapFirstUser with a
masked reader (promptMasked) that suppresses echo and requires the user
to type their password twice to confirm. Min-8-chars validation is
preserved and applied after both entries agree.

AC-4: Add a hooks-preview stage (hooksPreviewStage) between
runtimeSetupStage and skillsSelectStage in the wizard. The stage
parses hooks-config.json, displays each hook event/matcher/command,
and prompts the user for consent before installation. Declined → state
recorded with accepted=false. Also adds `mosaic config hooks list|enable|
disable` subcommands to manage installed hooks in ~/.claude/ post-install.

AC-5: Add headless install path to runConfigWizard and bootstrapFirstUser
gated on MOSAIC_ASSUME_YES=1 or !process.stdin.isTTY. Env-var-driven
configuration with required-var validation and non-zero exit on missing
or invalid inputs. Documents all env vars in packages/mosaic/README.md.

Closes #426

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/mosaic/src/commands/config.ts

@@ -1,8 +1,74 @@
 import { spawnSync } from 'node:child_process';
+import { existsSync, readFileSync, writeFileSync } from 'node:fs';
+import { join } from 'node:path';
+import { homedir } from 'node:os';
 import type { Command } from 'commander';
 import { createConfigService } from '../config/config-service.js';
 import { DEFAULT_MOSAIC_HOME } from '../constants.js';
 
+// ── Hooks management helpers ──────────────────────────────────────────────────
+
+const DISABLED_PREFIX = '_disabled_';
+
+/** Resolve the ~/.claude directory (allow override via CLAUDE_HOME env var). */
+function getClaudeHome(): string {
+  return process.env['CLAUDE_HOME'] ?? join(homedir(), '.claude');
+}
+
+interface HookEntry {
+  type?: string;
+  command?: string;
+  args?: unknown[];
+  [key: string]: unknown;
+}
+
+interface HookTrigger {
+  matcher?: string;
+  hooks?: HookEntry[];
+}
+
+interface HooksConfig {
+  name?: string;
+  hooks?: Record<string, HookTrigger[]>;
+  [key: string]: unknown;
+}
+
+function readInstalledHooksConfig(claudeHome: string): HooksConfig | null {
+  const p = join(claudeHome, 'hooks-config.json');
+  if (!existsSync(p)) return null;
+  try {
+    return JSON.parse(readFileSync(p, 'utf-8')) as HooksConfig;
+  } catch {
+    return null;
+  }
+}
+
+function writeInstalledHooksConfig(claudeHome: string, config: HooksConfig): void {
+  const p = join(claudeHome, 'hooks-config.json');
+  writeFileSync(p, JSON.stringify(config, null, 2) + '\n', { mode: 0o600 });
+}
+
+/**
+ * Collect a flat list of hook "names" for display purposes.
+ * A hook name is `<EventName>/<matcher>` (e.g. `PostToolUse/Write|Edit`).
+ */
+function listHookNames(config: HooksConfig): Array<{ name: string; enabled: boolean }> {
+  const results: Array<{ name: string; enabled: boolean }> = [];
+  const events = config.hooks ?? {};
+
+  for (const [rawEvent, triggers] of Object.entries(events)) {
+    const enabled = !rawEvent.startsWith(DISABLED_PREFIX);
+    const event = enabled ? rawEvent : rawEvent.slice(DISABLED_PREFIX.length);
+
+    for (const trigger of triggers) {
+      const matcher = trigger.matcher ?? '(any)';
+      results.push({ name: `${event}/${matcher}`, enabled });
+    }
+  }
+
+  return results;
+}
+
 /**
  * Resolve mosaicHome from the MOSAIC_HOME env var or the default constant.
  */
@@ -179,6 +245,138 @@ export function registerConfigCommand(program: Command): void {
       }
     });
 
+  // ── config hooks ────────────────────────────────────────────────────────
+
+  const hookCmd = cmd.command('hooks').description('Manage Mosaic hooks installed in ~/.claude/');
+
+  hookCmd
+    .command('list')
+    .description('List installed hooks and their enabled/disabled status')
+    .action(() => {
+      const claudeHome = getClaudeHome();
+      const config = readInstalledHooksConfig(claudeHome);
+
+      if (!config) {
+        console.log(
+          `No hooks-config.json found at ${claudeHome}.\n` +
+            'Run `mosaic wizard` to install hooks, or copy hooks-config.json manually.',
+        );
+        return;
+      }
+
+      const entries = listHookNames(config);
+
+      if (entries.length === 0) {
+        console.log('No hooks defined in hooks-config.json.');
+        return;
+      }
+
+      const maxName = Math.max(...entries.map((e) => e.name.length));
+      const header = `${'Hook'.padEnd(maxName)}  Status`;
+      console.log(header);
+      console.log('-'.repeat(header.length));
+
+      for (const { name, enabled } of entries) {
+        console.log(`${name.padEnd(maxName)}  ${enabled ? 'enabled' : 'disabled'}`);
+      }
+    });
+
+  hookCmd
+    .command('disable <name>')
+    .description('Disable a hook by name (prefix with _disabled_). Use "list" to see hook names.')
+    .action((name: string) => {
+      const claudeHome = getClaudeHome();
+      const config = readInstalledHooksConfig(claudeHome);
+
+      if (!config) {
+        console.error(
+          `No hooks-config.json found at ${claudeHome}.\n` +
+            'Nothing to disable. Run `mosaic wizard` to install hooks first.',
+        );
+        process.exit(1);
+      }
+
+      const events = config.hooks ?? {};
+      // Support matching by event key or by event/matcher composite
+      const [targetEvent, targetMatcher] = name.split('/');
+
+      // Find the event key (may already have DISABLED_PREFIX)
+      const existingKey = Object.keys(events).find(
+        (k) =>
+          k === targetEvent ||
+          k === `${DISABLED_PREFIX}${targetEvent}` ||
+          k.replace(DISABLED_PREFIX, '') === targetEvent,
+      );
+
+      if (!existingKey) {
+        console.error(`Hook event "${targetEvent}" not found.`);
+        console.error('Run `mosaic config hooks list` to see available hooks.');
+        process.exit(1);
+      }
+
+      if (existingKey.startsWith(DISABLED_PREFIX)) {
+        console.log(`Hook "${name}" is already disabled.`);
+        return;
+      }
+
+      const disabledKey = `${DISABLED_PREFIX}${existingKey}`;
+      const triggers = events[existingKey];
+      delete events[existingKey];
+
+      // If a matcher was specified, only disable that trigger
+      if (targetMatcher && triggers) {
+        events[disabledKey] = triggers.filter((t) => t.matcher === targetMatcher);
+        events[existingKey] = triggers.filter((t) => t.matcher !== targetMatcher);
+        if ((events[existingKey] ?? []).length === 0) delete events[existingKey];
+      } else {
+        events[disabledKey] = triggers ?? [];
+      }
+
+      config.hooks = events;
+      writeInstalledHooksConfig(claudeHome, config);
+      console.log(`Hook "${name}" disabled.`);
+    });
+
+  hookCmd
+    .command('enable <name>')
+    .description('Re-enable a previously disabled hook.')
+    .action((name: string) => {
+      const claudeHome = getClaudeHome();
+      const config = readInstalledHooksConfig(claudeHome);
+
+      if (!config) {
+        console.error(
+          `No hooks-config.json found at ${claudeHome}.\n` +
+            'Nothing to enable. Run `mosaic wizard` to install hooks first.',
+        );
+        process.exit(1);
+      }
+
+      const events = config.hooks ?? {};
+      const targetEvent = name.split('/')[0] ?? name;
+      const disabledKey = `${DISABLED_PREFIX}${targetEvent}`;
+
+      if (!events[disabledKey]) {
+        // Check if it's already enabled
+        if (events[targetEvent]) {
+          console.log(`Hook "${name}" is already enabled.`);
+        } else {
+          console.error(`Disabled hook "${name}" not found.`);
+          console.error('Run `mosaic config hooks list` to see available hooks.');
+          process.exit(1);
+        }
+        return;
+      }
+
+      const triggers = events[disabledKey];
+      delete events[disabledKey];
+      events[targetEvent] = triggers ?? [];
+
+      config.hooks = events;
+      writeInstalledHooksConfig(claudeHome, config);
+      console.log(`Hook "${name}" enabled.`);
+    });
+
   // ── config path ─────────────────────────────────────────────────────────
 
   cmd