feat: render kato summaries per-channel (markdown|json)

[zufardhiyaulhaq]

Summary

kato now emits a summaryFormat marker (markdown or json) alongside each summary. This teaches kato-bot to read that marker and convert either format into what each chat platform needs — fixing Telegram showing raw Markdown (##, **, `) as literal characters.

• Lark consumes Markdown natively → stays Markdown.
• Telegram needs a restricted HTML subset → we convert to <b>/<i>/<code>/<pre>/<a> with proper escaping.

What changed

• internal/summaryfmt (new, tested): ToMarkdown(summary, format) and ToTelegramHTML(summary, format). Handles both kato Markdown and the json {verdict, headline, blocks[]} schema. Markdown is the canonical hub: json blocks are normalized to Markdown, then Telegram HTML is produced from that single path. Code spans and links are protected so emphasis never bleeds into them; <, >, & are escaped.
• Read the marker: summaryFormat added to the kato client, core.RunResult, and core.ServiceResult (+ threaded through the group runner).
• Single-run result: Telegram (keyboards.go) renders HTML; Lark (cards.go) renders Markdown.
• Group run: per-service Lark cards (groupcards.go) + the Telegram group summary (dispatch.go).

Before / after (Telegram)

Before: ## Diagnosis / **web** / - item shown literally.
After: Diagnosis (bold), web bold, • item bullets, <code>/<pre> for code, entities escaped.

Testing

• go build ./..., go vet ./..., go test ./... — all green (existing Lark/Telegram tests included, no regressions).
• New summaryfmt tests cover markdown→HTML, json→markdown, json→HTML, escaping, fenced code, and code-span emphasis suppression.

Pairs with gopaytech/kato#1 (the kato side that emits summaryFormat).

🤖 Generated with Claude Code