update: update the dev-docs for AI agent

dev-docs/ai-guidelines.md

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+# AI Integration Guidelines
+
+## Search design
+
+Search should support at least two useful modes:
+
+### 1. Field-aware structured search
+Examples: tags, authors, categories, titles, summary fields
+
+### 2. Full-text-friendly search
+Support grep-like workflows and integration with tools such as `ripgrep`.
+
+Do not require semantic/vector search as a baseline feature.
+
+If semantic search is ever added later, it should be optional and must not displace simple grep/database search.
+
+## Summarization design
+
+Summarization should produce reusable structured outputs.
+
+### Summarization goals
+
+A summary should be useful for:
+- later human review
+- grep-style reverse lookup
+- building daily/weekly reports
+- indexing by problem/method/result
+- personal research triage
+
+### Summarization output
+
+Prefer generating:
+- `summary.json` as the canonical structured output
+- `summary.md` rendered from JSON
+
+Do not make free-form Markdown the only output.
+
+### Prompting guidelines
+
+Prompts should instruct the model to:
+- extract factual information
+- avoid unsupported claims
+- use concise and stable language
+- prefer controlled vocabulary when available
+- return structured JSON only
+- use `null` or empty lists for unclear fields rather than hallucinating
+
+### Provider abstraction
+
+The summarizer should not be tightly coupled to a single LLM provider.
+
+Use a provider abstraction so the project can support:
+- OpenAI-compatible APIs
+- local models later if desired
+- different prompt templates and vocabularies