feat(extraction): add IncidentReport schema and harden LLM extraction

[Fadhili5]

• Add src/schemas/incident_report.py: canonical Pydantic model covering all fields needed across Cal Fire FIRESCOPE, EMS, and law enforcement forms (identity, location, timestamps, personnel, casualties, wildfire, narrative, law enforcement sections)
• Add model_validator that auto-populates requires_review for any core field left null after extraction, so responders can spot gaps before PDF submission
• Add llm_schema_hint() classmethod that returns the JSON schema minus requires_review, used to build the structured Ollama system prompt
• Refactor LLM class: replace per-field prompt loop with a single structured request using Ollama format="json" and Mistral instruction format ([INST]...[/INST])
• LLM now returns IncidentReport via get_report() in addition to the existing get_data() dict accessor for backward compatibility
• Fix test_submit_form: replace stub with a working integration test that creates a template then mocks Controller to assert the full POST /forms/fill response shape