fix(native): require publication for files named under a Deliverable label (#20231)

## Thinking Path

> - Paperclip is the open source app people use to manage AI agents for
work
> - Native agents finish a task with a completion report, and a server
gate checks that requested files are published to the task
> - The gate finds a file request only from a creation verb, such as
"Write report.pdf"
> - Delegated briefs often list the output under a "Deliverable:" label
instead, and the gate did not know `.html` or `.css` names
> - So a worker can finish a website task with `index.html` only in its
own workspace, and the person cannot open it
> - This pull request makes a file named under a Deliverable label a
requested file output
> - The benefit is that the worker gets the existing "use
register_deliverable" feedback before the task closes

## Linked Issues or Issue Description

No public issue exists. Bug description:

**What happened**
A person asked the CEO: "Make me a simple website introducing our
business." The CEO delegated a task. Its brief said "Deliverable: - A
self-contained static website in this task's workspace: index.html plus
a stylesheet (for example styles.css)". The worker wrote `index.html`
and `styles.css` in its workspace. It did not call
`register_deliverable`. It cited `index.html` and `styles.css` as
completion evidence, and the gate accepted the report. The task was
marked done with no attachment. The CEO then told the person that the
files were "in the task workspace".

**Expected behavior**
A brief that names a file as its deliverable is a file request. The
completion gate must reject a workspace-only file and tell the worker to
publish it with `register_deliverable`.

**Steps to reproduce**
1. Call `explicitlyRequestsFileOutput` with the brief above.
2. See that it returns `false`, so `validateNativeDeliverableEvidence`
accepts the bare `index.html` evidence ref.

## What Changed

- `explicitlyRequestsFileOutput` now also returns true when a
`Deliverable:` / `Deliverables` label line (plain, bold or heading), or
a bullet or numbered item in the list below it (blank lines between
items allowed), names a file. Relative paths such as `dist/index.html`
count.
- Under the label, web page files (`.html`, `.htm`, `.css`) count with
the existing file types.
- Items that name an input ("a summary of input.csv", "a comparison of
input.csv and baseline.csv"), describe a repository change, pull
request, commit or branch, forbid the named file (`do not create
report.pdf`), name a file to edit in place (`update styles.css`) without
asking to publish it, send the file inline (`index.html and styles.css
inline in the reply`), or forbid creating files, do not count. An inline
or no-upload instruction about another output in the same item
(`index.html and a short summary in the reply`, `index.html; do not
upload it externally`) does not cancel the named file. The
repository-change check ignores file names, so `branch-report.pdf` still
counts.
- The sentence-based detector is unchanged.
- `doc/AGENT-ARTIFACTS.md` describes the label rule.

## Verification

- `cd server && npx vitest run
src/services/native-runtime/native-deliverable-feedback.test.ts
src/services/native-runtime/native-runner-file-handoff.test.ts` (197
pass), then after the review fixes
`native-deliverable-feedback.test.ts`,
`native-completion-format-feedback.test.ts` and
`chat-attachment-reuse.test.ts` (211 pass). The 13 first-round review
cases fail on the original head.
- New cases: the real delegated brief, inline labels, heading lists,
numbered lists and bold labels require publication. Unlabelled text,
inline-chat deliverables, input references, repository changes, text
after the list ends, and "Deliverable quality ..." prose do not.
- The chat eval `onboarding.first-work` exercises this path end to end
on its candidate branch.

## Risks

- Low risk. The change only adds a true result for labelled file
outputs; an inline-only or no-file label item stays false, as the
sentence detector already decided.
- A labelled brief that names a file which is not a repository change
now needs `register_deliverable` or an accessible work product. That is
the documented delivery rule.

## Model Used

- Anthropic Claude Opus 5.5 (`claude-opus-5-5`), tool use and code
execution in Claude Code.

## Checklist

- [x] I have included a thinking path that traces from project context
to this change
- [x] I have specified the model used (with version and capability
details)
- [x] I have checked ROADMAP.md and confirmed this PR does not duplicate
planned core work
- [x] I have searched GitHub for duplicate or related PRs and linked
them above
- [x] I have either (a) linked existing issues with `Fixes: #` / `Closes
#` / `Refs #` OR (b) described the issue in-PR following the relevant
issue template
- [x] I have not referenced internal/instance-local Paperclip issues or
links (only public GitHub `#NNN` / `github.com/paperclipai/paperclip`
URLs)
- [x] My branch name describes the change (e.g. `docs/...`, `fix/...`)
and contains no internal Paperclip ticket id or instance-derived details
- [x] I have run tests locally and they pass
- [x] I have added or updated tests where applicable
- [x] I have updated relevant documentation to reflect my changes
- [x] I have considered and documented any risks above
- [ ] All Paperclip CI gates are green
- [ ] Greptile is 5/5 with no open P2s, recommendations, or follow-ups
- [x] I will address all Greptile and reviewer comments before
requesting merge

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

doc/AGENT-ARTIFACTS.md

@@ -34,6 +34,18 @@ their contents inline does not by itself require a file attachment.
 JSON output intent is recognized from a direct filename or an explicit output
 destination. Ambiguous descriptions of input files joined by `to` remain text
 requests; use `as`, `into`, or an explicit output file when an artifact is required.
+A `Deliverable:` or `Deliverables` label also states the output. A file named
+on that line, or in the list directly below it (blank lines between items are
+allowed), is a requested file. This includes relative paths such as
+`dist/index.html` and web page files such as `index.html` and `styles.css`.
+Items that describe a repository change, pull request, commit, or branch do
+not count, nor do files named as inputs (`a comparison of input.csv and
+baseline.csv`), files the item forbids (`do not create report.pdf`), files to
+be edited in place (`update styles.css`) unless the item also asks to publish
+them, files to be written inline in the reply (`index.html and styles.css inline
+in the reply`), or items that say no files are created. An inline or no-upload
+instruction about another output in the same item does not cancel a named file
+(`index.html and a short summary in the reply`).
 
 The completion gate permits a narrow sentence-bound exception for one requested
 file when the following sentence explicitly qualifies it, for example: