[Fix] Tool approvals work for calls made without arguments

[daniel-lxs]

Related issue

Internal follow-up to #3001; no separate issue is linked.

Why this PR exists

• A maintainer explicitly invited this PR in the linked issue or discussion
• I am a maintainer / this is internal Roomote work

What changed

A tool call made with no arguments (for example a list_files tool whose arguments are all optional) couldn't be recorded for approval. Its argument summary was null, args_summary is NOT NULL, and the insert failed. The bridge then rejected the call, so the user saw no card, and the agent reported that the approval "did not complete".

The approval and Auto evaluation insert helpers now record a call without arguments as {}. That covers session calls, task calls, and background assessments.

How it was tested

• New DB test: pending, auto-approved and auto-rejected rows for a call with no arguments. It fails on develop with the same null value in column "args_summary" error and passes with the fix. All 31 approval DB tests pass.
• Found live on a local stack: a session with Auto on, where the agent called a local MCP server's list_files with no arguments. Retested live with the fix: see the combined smoke notes on the related PRs.

Checklist

• The PR title follows the repo convention: [Fix], [Feat], [Improve], [Refactor], [Docs], or [Chore] followed by a user-facing description
• This PR is small and scoped to one change
• pnpm lint and pnpm check-types pass locally
• I added tests or included a clear manual validation note above
• I removed secrets, tokens, private keys, and customer data from code, logs, and screenshots
• If this change should appear in the changelog, I ran pnpm changeset

Combined local smoke (2026-09-30)

All six Auto/approval PRs (#3332, #3334, #3335, #3337, #3338, #3339) were merged together locally and run on a local stack. It used a real web session with Auto on, Jev through OpenRouter, and a local MCP server whose tools only log (list_files, delete_file, pay_invoice). The PRs merge cleanly into develop in any order, except #3332 and #3337: both add an export next to each other in packages/types, and whichever lands second needs a trivial rebase. The combined build passes uncached pnpm check-types, pnpm lint, and the approval suites (cloud-agents 131, sdk 23, worker 13, db 32).

#	Scenario	PR	Result
S1	"Delete old-notes.txt": the delete runs with no card	#3335, #3338	Pass. delete_file auto-approved (authorization 0.97, highest risk level). A list_files with no arguments now shows a card instead of failing the insert.
S2	"Pay invoice INV-11 for $120": asks, even though requested	#3335, #3339	Pass. A card on the first attempt (it used to be auto-rejected as "away" in a new session), and the call never ran.
S3	A subagent calls an Ask first tool	#3334	Pass. A card appeared and the call ran after Allow once. The subagent's list_files was assessed by Auto (auto-approved row).
S4	Flagged call while the owner is away	#3332, #3339	Pass. Auto-rejected about 19 seconds after the message (presence recheck). The agent said "When you're back, ask again", with no mention of the transcript.
S5	Judgment model unavailable	#3337	Pass. Two calls failed together, both were rejected, one notice was posted, and the session was marked paused. After "ok, continue", both got plain cards and ran once allowed.
S6	Auto turned off after a pause	#3337	Pass. The next call ran with no card (new turn; the mid-turn path is covered by a unit test).
S7	"Delete draft-1, draft-2 and draft-3": all run	#3335	Pass. Three deletes auto-approved (authorization 0.92 to 0.96), no cards.

Not covered live: chat surfaces (Slack, Telegram, Discord) and the task (sandbox) path, because there's no local worker. Both are covered by unit tests.

[roomote-community]

No code issues found. See task

_{Reviewed 3495848}