feat(routines): add minoxidil beard/mustache option to routine suggestions

- Add include_minoxidil_beard flag to SuggestRoutineRequest and SuggestBatchRequest
- Detect minoxidil products by scanning name, brand, INCI and actives; pass them
  to the LLM even though they are medications
- Inject CELE UŻYTKOWNIKA context block into prompts when flag is enabled
- Add _build_objectives_context() returning empty string when flag is off
- Add call_gemini() helper that centralises Gemini API calls and logs every
  request/response to a new ai_call_logs table (AICallLog model + /ai-logs router)
- Nginx: raise client_max_body_size to 16 MB for photo uploads

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

backend/alembic/versions/a1b2c3d4e5f6_add_ai_call_logs.py

@@ -0,0 +1,51 @@
+"""add_ai_call_logs
+
+Revision ID: a1b2c3d4e5f6
+Revises: c2d626a2b36c
+Create Date: 2026-03-01 00:00:00.000000
+
+"""
+
+from typing import Sequence, Union
+
+import sqlalchemy as sa
+import sqlmodel.sql.sqltypes
+
+from alembic import op
+
+revision: str = "a1b2c3d4e5f6"
+down_revision: Union[str, None] = "c2d626a2b36c"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        "ai_call_logs",
+        sa.Column("id", sa.Uuid(), nullable=False),
+        sa.Column("created_at", sa.DateTime(timezone=True), nullable=False),
+        sa.Column("endpoint", sqlmodel.sql.sqltypes.AutoString(), nullable=False),
+        sa.Column("model", sqlmodel.sql.sqltypes.AutoString(), nullable=False),
+        sa.Column("system_prompt", sa.Text(), nullable=True),
+        sa.Column("user_input", sa.Text(), nullable=True),
+        sa.Column("response_text", sa.Text(), nullable=True),
+        sa.Column("prompt_tokens", sa.Integer(), nullable=True),
+        sa.Column("completion_tokens", sa.Integer(), nullable=True),
+        sa.Column("total_tokens", sa.Integer(), nullable=True),
+        sa.Column("duration_ms", sa.Integer(), nullable=True),
+        sa.Column("success", sa.Boolean(), nullable=False),
+        sa.Column("error_detail", sa.Text(), nullable=True),
+        sa.PrimaryKeyConstraint("id"),
+    )
+    op.create_index(
+        op.f("ix_ai_call_logs_endpoint"), "ai_call_logs", ["endpoint"], unique=False
+    )
+    op.create_index(
+        op.f("ix_ai_call_logs_success"), "ai_call_logs", ["success"], unique=False
+    )
+
+
+def downgrade() -> None:
+    op.drop_index(op.f("ix_ai_call_logs_success"), table_name="ai_call_logs")
+    op.drop_index(op.f("ix_ai_call_logs_endpoint"), table_name="ai_call_logs")
+    op.drop_table("ai_call_logs")