sync system_prompt.md from #326 (drift check red on every PR)

[suleimansh]

Issue #326's system-prompt block was edited today (~15:26), so the drift check now fails on every PR (first seen on #1426; the #1425 merge CI at 15:17 was still green). This is the documented fix: copy block 1 into prompts/system_prompt.md verbatim.

What the issue edit changed (all followed verbatim here):

• TODO_FILE: \TODO_AGENTS.md`` glossary line restored
• the very-large-scope bullet uses <TODO_FILE>/<SHOW_MD> placeholders again
• the terminal instruction is back to "consider whether <SESSION_NAME> is finished … then call setReadyForMerge()" — i.e. the Auto-merge requires the agent's setReadyForMerge signal (#1363) #1392 "required, the work is never merged without it" tightening is gone from the issue

@brillout flagging that last one for visibility: if the softening was deliberate, nothing to do (the merge gate itself is code — withheldMerge still blocks a merge without the signal, so the worst case is more withheld draft PRs on weaker models, per the #1334 tier table). If it was an accidental restore of an older block, edit the issue and this file can be re-synced.

Drift check passes locally against the live issue; suite 1650/0.

🤖 Generated with Claude Code

[brillout]

Mistake?

[suleimansh]

Yes, I think its mistake

[brillout]

Smells like a bug though... do agents always make sure their work on top of origin/main after git fetch?

Btw. the whole commit that commits uncommitted changes isn't needed anymore since we have worktrees. (This is the kind of bugs we should manage to fix without much discussion. Such major bug (a blocker really) should always be fixed.)

[suleimansh]

Root cause found, and it's not an agent-rebase bug: issue #326 hadn't been edited since Jul 27 — #1392 tightened the wording in the repo file only, so the repo was ahead of the issue, and this PR's first sync followed the drift check's "issue is the source of truth" instruction backwards into a revert. Fixed properly now: the issue is updated (tightened wording restored, your <TODO_FILE> suggestion, and the uncommitted-changes step removed per your comment — worktree runs start clean, the step only made junk commits), and the branch re-synced to it. Drift green, suite 1650/0.

[brillout]

Hm, I still consider it a bug (maybe a merge conflict bug), but let's see if this occurs again.