Summarize tone: re-summarize in a chosen voice (backend)

POST /reprocess?job=summarize&tone=<voice> persists the voice on the job
row (queue carries only ids, so a sweep re-enqueue keeps it), the LLM
prompt appends 'write every field in a <tone> tone — the tone colors
the wording, never the facts', and the resulting summary records its
tone (SummaryOut.tone). Plain re-summarize clears a previous tone.
Migration tone0000000001 (summaries.tone, processing_jobs.tone).
78 passed, 1 skipped; ruff clean.

backend/migrations/versions/tone0000000001_summary_tone.py

@@ -0,0 +1,36 @@
+"""summary tone: summarize-in-a-different-voice support
+
+Revision ID: tone0000000001
+Revises: m8models000001
+Create Date: 2026-09-15
+
+- summaries.tone  (voice the summary was written in; NULL = neutral)
+- processing_jobs.tone (pending request; survives sweep re-enqueue)
+"""
+from __future__ import annotations
+
+from collections.abc import Sequence
+
+import sqlalchemy as sa
+from alembic import op
+
+revision: str = "tone0000000001"
+down_revision: str | None = "m8models000001"
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
+
+
+def upgrade() -> None:
+    op.add_column(
+        "summaries",
+        sa.Column("tone", sa.String(length=64), nullable=True),
+    )
+    op.add_column(
+        "processing_jobs",
+        sa.Column("tone", sa.String(length=64), nullable=True),
+    )
+
+
+def downgrade() -> None:
+    op.drop_column("processing_jobs", "tone")
+    op.drop_column("summaries", "tone")