fix(process): derive target date from message send day, not processing day

A message sent yesterday but processed today (e.g. by the next service
run) landed in today's daily note. The send time was captured in
received_at but only HH:MM reached the LLM; the date defaulted to
date.today(). Now today/weekday in the processor context are derived per
item from received_at, so "gestern"/"heute" resolve relative to when the
message was actually written. Adds day_context() helper and a regression
test (sent 2026-06-25, processed 2026-06-26 -> note 2026-06-25).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/journal_bot/context.py

@@ -21,6 +21,11 @@ def _read_frontmatter(text: str) -> dict[str, str]:
     return out
 
 
+def day_context(d: date) -> dict:
+    """today/weekday for a given date (the message's send day)."""
+    return {"today": d.isoformat(), "weekday": WEEKDAYS_DE[d.weekday()]}
+
+
 def collect_vault_context(vault_path: Path, today: date) -> dict:
     persons: list[dict] = []
     persons_dir = vault_path / "00 Kontext" / "Personen"

src/journal_bot/process.py

@@ -1,6 +1,6 @@
 from datetime import date, datetime
 from pathlib import Path
-from .context import collect_vault_context
+from .context import collect_vault_context, day_context
 from .queue import Queue
 from .vault_writer import VaultWriter
 from .processor_protocol import ProcessorInput
@@ -18,9 +18,14 @@ def process_once(processor, queue: Queue, writer: VaultWriter, vault_path: Path,
         try:
             received_dt = datetime.fromisoformat(item.received_at)
             received_time = received_dt.strftime("%H:%M")
+            # Default day is the message's SEND day, not the processing day,
+            # so a message sent yesterday but processed today lands in
+            # yesterday's note. "gestern"/"heute" in the text are relative
+            # to the send day. Fall back to `today` if received_at is unusable.
+            send_day = day_context(received_dt.date())
             payload = ProcessorInput(
-                today=ctx["today"],
+                today=send_day["today"],
-                weekday=ctx["weekday"],
+                weekday=send_day["weekday"],
                 received_time=received_time,
                 persons=ctx["persons"],
                 projects=ctx["projects"],

src/journal_bot/prompts/journal_system.md

@@ -15,7 +15,7 @@ Antworte ausschließlich mit einem JSON-Objekt nach folgendem Schema. Kein Flie
 
 # Regeln
 
-1. **target_date:** Standard = `today` aus dem Context. Bei „gestern" → today − 1, „vorgestern" → today − 2. Bei explizitem Datum (z.B. „am 12. Juni") dieses verwenden.
+1. **target_date:** Standard = `today` aus dem Context. `today` ist der **Sendetag der Nachricht** (nicht der Verarbeitungstag), also der Tag, an dem Christian die Nachricht geschrieben hat. Bei „gestern" → today − 1, „vorgestern" → today − 2 (relativ zum Sendetag). Bei explizitem Datum (z.B. „am 12. Juni") dieses verwenden.
 2. **target_path:** Immer `05 Daily Notes/{target_date}.md`.
 3. **entry_markdown:** Beginnt IMMER mit `## HH:MM`. Nutze `received_time` aus dem Context.
 4. **Meta-Anweisungen entfernen:** Phrasen wie „Schreib ins Journal, dass …", „Notier dir, dass …", „Merk dir …" gehören NICHT in den Eintragstext. Liste sie in `raw_excluded`.

tests/test_process.py

@@ -22,6 +22,23 @@ class FakeProcessor:
         return self._output
 
 
+class CapturingProcessor:
+    """Records the payload it was asked to process and echoes today as target."""
+    def __init__(self):
+        self.payload = None
+
+    def health_check(self):
+        return True
+
+    def process(self, payload):
+        self.payload = payload
+        return ProcessorOutput(
+            target_date=payload.today,
+            target_path=f"05 Daily Notes/{payload.today}.md",
+            entry_markdown=f"## {payload.received_time}\n{payload.text}",
+        )
+
+
 def make_item(update_id=1, text="Hallo"):
     return QueueItem(
         update_id=update_id,
@@ -74,6 +91,35 @@ def test_process_fails_item_on_error(tmp_path):
     assert data["attempts"] == 1
 
 
+def test_target_date_follows_send_day_not_processing_day(tmp_path):
+    # Message sent yesterday (2026-06-25), processed today (2026-06-26).
+    # The daily note must be the send day, not the processing day.
+    vault = tmp_path / "vault"
+    (vault / "05 Daily Notes").mkdir(parents=True)
+    queue = Queue(tmp_path / "q")
+    item = QueueItem(
+        update_id=1,
+        received_at="2026-06-25T08:13:42+02:00",
+        type="text",
+        text="Neue Charge Kefir angesetzt",
+    )
+    queue.enqueue(item)
+    processor = CapturingProcessor()
+    writer = VaultWriter(vault)
+    process_once(
+        processor, queue, writer,
+        vault_path=vault,
+        today=date(2026, 6, 26),  # processing day differs from send day
+        processed_at="2026-06-26T06:55:22+02:00",
+    )
+    # The processor must have been told today = the send day, with matching weekday.
+    assert processor.payload.today == "2026-06-25"
+    assert processor.payload.weekday == "Donnerstag"  # 2026-06-25 is a Thursday
+    # And the entry landed in the send-day note.
+    data = json.loads((tmp_path / "q" / "done" / "1.json").read_text(encoding="utf-8"))
+    assert data["target_path"] == "05 Daily Notes/2026-06-25.md"
+
+
 def test_process_records_result_fields(tmp_path):
     vault = tmp_path / "vault"
     (vault / "05 Daily Notes").mkdir(parents=True)