feat(timezone): recreate v1 TZ-aware formatting + scheduling behavior

The agent needs to perceive times in the user's timezone, not UTC.
Dropping this in the v1→v2 port produced a class of bugs where the agent
would schedule tasks for the wrong hour, suggest dinner at midnight, etc.
This restores v1 parity.

Container side:
- New container/agent-runner/src/timezone.ts mirrors src/timezone.ts with
  isValidTimezone / resolveTimezone / formatLocalTime, plus:
  * TIMEZONE constant resolved at load from process.env.TZ (host sets this
    from src/container-runner.ts:254)
  * parseZonedToUtc(input, tz) — treats a naive ISO as wall-clock time in
    `tz`, returns the corresponding UTC Date. Strings with Z or offset
    are passed through.

- formatter.ts:
  * formatMessages() now prepends <context timezone="IANA"/>\n — matches
    v1 src/v1/router.ts:20-22
  * formatSingleChat uses formatLocalTime(ts, TIMEZONE) instead of a
    home-rolled HH:MM 24h formatter → outputs like "Jun 15, 2026, 8:00 AM"
  * reply_to="<id>" attribute + <quoted_message from="X">Y</quoted_message>
    element — matches v1 format exactly; old <reply-to/> shape is gone
  * stripInternalTags() exported for the dispatch path to reuse

- poll-loop.ts uses the exported stripInternalTags() instead of inline regex.

- mcp-tools/scheduling.ts:
  * schedule_task/update_task descriptions now explicitly document that
    processAfter accepts either UTC or naive local time (interpreted in
    the user's TZ from the context header)
  * handlers normalize through parseZonedToUtc() and store a UTC ISO

Host side:
- src/modules/scheduling/recurrence.ts passes { tz: TIMEZONE } to
  CronExpressionParser.parse. Without this, "0 9 * * *" fires at 09:00
  UTC instead of 09:00 user-local — this was the v1 behavior
  (src/v1/task-scheduler.ts:20-49).

Tests:
- container/agent-runner/src/timezone.test.ts — mirror of src/timezone.test.ts
  + new parseZonedToUtc cases
- container/agent-runner/src/formatter.test.ts — context header, reply_to,
  quoted_message, XML escaping, stripInternalTags (ported from v1
  formatting.test.ts)
- src/modules/scheduling/recurrence.test.ts — cron TZ respected, completed
  rows only cloned when recurrence is set

Ref: docs/v1-vs-v2/ACTION-ITEMS.md item 18 + timezone-formatting-v1-recreation.md

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/modules/scheduling/recurrence.ts

@@ -13,6 +13,7 @@
  */
 import type Database from 'better-sqlite3';
 
+import { TIMEZONE } from '../../config.js';
 import { log } from '../../log.js';
 import type { Session } from '../../types.js';
 import { clearRecurrence, getCompletedRecurring, insertRecurrence } from './db.js';
@@ -23,7 +24,11 @@ export async function handleRecurrence(inDb: Database.Database, session: Session
   for (const msg of recurring) {
     try {
       const { CronExpressionParser } = await import('cron-parser');
-      const interval = CronExpressionParser.parse(msg.recurrence);
+      // Interpret the cron expression in the user's timezone. v1 did this
+      // (src/v1/task-scheduler.ts:20-49); without it, a task written "0 9 * * *"
+      // by an agent running in a user's local TZ fires at 09:00 UTC instead of
+      // 09:00 user-local.
+      const interval = CronExpressionParser.parse(msg.recurrence, { tz: TIMEZONE });
       const nextRun = interval.next().toISOString();
       const prefix = msg.kind === 'task' ? 'task' : 'msg';
       const newId = `${prefix}-${Date.now()}-${Math.random().toString(36).slice(2, 8)}`;