feat: add auto-pagination to messages search and update lark-im docs

[YangJunzhou-01]

Summary

This PR adds auto-pagination support to im +messages-search and updates the related lark-im docs to match the new behavior.

The change keeps the default behavior unchanged for existing users:

• default remains single-page
• users can opt into auto-pagination with --page-all
• users can set an explicit cap with --page-limit <n>

Background

im +messages-search previously returned only a single page of results unless callers manually resumed with --page-token.

That was workable for simple lookups, but it was awkward for:

• work summary / weekly report generation
• broad keyword searches across active chats
• cases where search results exceeded one page and callers needed a complete dataset

This PR addresses that gap while preserving backward compatibility.

What Changed

1. Add auto-pagination to im +messages-search

New flags:

• --page-all
• --page-limit <n>

Behavior:

• default is still single-page
• --page-all enables auto-pagination with a max cap of 40 pages
• --page-limit <n> enables auto-pagination with an explicit cap
• passing --page-limit without --page-all still enables auto-pagination
• when pagination stops due to the configured cap, output still returns has_more / page_token so callers can resume manually

2. Keep large follow-up fetches batched

Search execution now:

1. fetches message search pages
2. batch-fetches message details via messages/mget in chunks of up to 50 IDs
3. batch-fetches chat context via chats/batch_query in chunks of up to 50 chat IDs

This keeps the implementation aligned with downstream API limits and makes multi-page search results usable in practice.

3. Improve dry-run / help text

Dry-run output now reflects:

• whether auto-pagination is enabled
• the effective page cap
• that message detail and chat-context enrichment happen in batches

Shortcut description and help text were also updated to mention:

• auto-pagination support
• batched mget / chat context enrichment

4. Update lark-im docs

Updated:

• skills/lark-im/SKILL.md
• skills/lark-im/references/lark-im-messages-search.md

Docs now cover:

• --page-all / --page-limit
• pagination behavior and resume strategy
• report-generation guidance for multi-page search
• actual p2p output fields

Also corrected the p2p field description to match current implementation:

• chat_name is documented for group chats
• chat_partner for p2p is documented as containing open_id

Compatibility / Behavior Notes

• No breaking change to default behavior: single-page remains the default.
• Existing manual pagination with --page-token continues to work.
• --page-limit is validated as an integer in the range 1..40.
• Pretty output shows a warning when results were truncated by the configured page cap.

Tests

Added / updated coverage for:

• invalid --page-limit validation
• pagination config behavior
• dry-run output shape
• execute path with multi-page search
• batched mget calls
• batched batch_query calls
• explicit --page-limit without --page-all

Test command:

go test ./shortcuts/im/...

## Example Usage

# default: single page
lark-cli im +messages-search --query "incident"

# fetch automatically up to the default auto-pagination cap
lark-cli im +messages-search --query "incident" --page-all --format json

# fetch automatically with an explicit cap
lark-cli im +messages-search --query "incident" --page-limit 5 --format json

# resume manually if capped response still has_more=true
lark-cli im +messages-search --query "incident" --page-token <token> --format json

[CLAassistant]

All committers have signed the CLA.

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Codecov Report

❌ Patch coverage is 87.73585% with 13 lines in your changes missing coverage. Please review.
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Files with missing lines	Patch %	Lines
shortcuts/im/im_messages_search.go	87.73%	6 Missing and 7 partials ⚠️
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