## Stack
1. [1 of 3] Support long raw TUI goal objectives - #27508
2. **[2 of 3] Support long pasted text in TUI goals** - this PR
3. [3 of 3] Support images in TUI goals - #27510
## Why
Large text pasted into the TUI composer is represented as a paste
placeholder plus pending paste metadata. For `/goal`, preserving only
the visible placeholder is not enough: the agent would see a short
placeholder string instead of the actual pasted text, and the long-text
support from the first PR would never see the payload.
The TUI also needs to avoid writing stale sidecar files when a user
pastes a large block and then deletes its placeholder before submitting
the goal.
## What Changed
- Introduces a TUI `GoalDraft` for goal submissions so `/goal`, `/goal
edit`, and queued goal commands can carry objective text plus text
elements and pending paste payloads.
- Materializes active pasted-text placeholders to `pasted-text-N.txt`
files through the app-server filesystem path introduced in #27508.
- Rewrites active paste placeholders in the persisted objective to file
references, while leaving literal placeholder-looking text alone.
- Filters out deleted paste placeholders so otherwise-small goals do not
require `$CODEX_HOME` or remote filesystem writes.
- Preserves pending paste metadata when a `/goal` command is queued
before a thread exists.
## Verification
- Added goal materialization tests for active paste placeholders,
deleted paste placeholders, and whitespace-only paste payloads.
- Added/updated TUI slash-command tests for large pasted text, queued
`/goal` commands before thread start, and queued oversized goal
behavior.
## Manual Testing
- Used real terminal bracketed-paste sequences through a remote TUI
session. A 1,228-byte multiline paste became `pasted-text-1.txt`; its
first/last lines and byte count matched exactly, and the persisted
objective referenced the server-host path.
- Pasted a large block, deleted its placeholder, and submitted a small
replacement objective. No new directory or sidecar file was created.
- Added two same-length large pastes to one goal. The composer
disambiguated their visible placeholders, and materialization preserved
order and contents in `pasted-text-1.txt` and `pasted-text-2.txt`.
- Submitted a whitespace-only large paste and verified the goal was
rejected as empty without writing a file.
- Submitted a pasted-text replacement while another goal was active,
verified no file was written before confirmation, then canceled and
confirmed the original goal remained unchanged.
- Combined a large paste with enough raw text to exceed 4,000 characters
after placeholder rewriting. The paste sidecar and `goal-objective.md`
were created in the same remote attachment directory, and `/goal edit`
restored the rewritten objective with its sidecar reference.
Eric Traut
c0f1ec5afd