docs: Objective is the Promachos working in Chromeria

[lukemaj]

What: OBJECTIVE.md now names the Promachos working in Chromeria as the current milestone.
Why: The previous Objective's core, retiring the Python runner, is done (#107), and the user decided on 2026-10-01 to make the Promachos architecture the next milestone.
So what: Merging confirms the new direction; the spec Issue and its tickets then fall inside the Objective.

Change

Only OBJECTIVE.md changes. Vision and Mission are unchanged. The triad is 1,392 characters, now inside the 1,500 cap (it was 2,249).

The Objective is complete when Promachos mode chats in bubbles with his persona from his home, Wight mode keeps a thread working until its timer or a subscription limit stops it, Drafters start in any project as children or top-level threads, and a Spectrum runs council and free modes compared in judged tests. VMs and mobile builds stay outside.

Mission still says OpenBot brings "Bots, Channels and the Computer". The glossary in #111 now calls these the Promachos and the Spectrum; updating the Mission wording is the user's call and is not part of this PR.

To revert: close this PR, or revert its commit after merge.

Elon record

Requirements and who asked: Change the Objective now that the runner is retired (user, 2026-10-01); the Promachos design settled in the same conversation.
Deleted: The old criteria (rebase routine, dispatch modes, runner retirement, OpenBot spike) and the "OpenBot mode UI is outside" exclusion; the triad's 749 characters over budget.
Bottleneck: User confirmation of direction, which merging this PR gives.
Checked myself: The triad size (190 + 789 + 413 bytes), that the runner hooks were removed in #107, and that the Objective advances the Mission's "OpenBot becomes a mode switched in the UI".

🤖 Generated with Claude Code

[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	13.6 KiB	13.6 KiB	−4 B (−0.0%)	15.1 KiB	✅
Codex	Thread snapshot wire	7.1 KiB	7.1 KiB	−1 B (−0.0%)	7.3 KiB	✅
Codex	Live turn WebSocket wire	6.5 KiB	6.5 KiB	−3 B (−0.0%)	7.8 KiB	✅
Codex	Live turn WebSocket decoded	56.3 KiB	56.3 KiB	0 B (0.0%)	66.4 KiB	✅
Codex	Live turn messages	10	10	0 (0.0%)	21	✅
Claude	Total thread wire	13.5 KiB	13.5 KiB	+2 B (+0.0%)	15.1 KiB	✅
Claude	Thread snapshot wire	7.1 KiB	7.1 KiB	+7 B (+0.1%)	7.3 KiB	✅
Claude	Live turn WebSocket wire	6.5 KiB	6.4 KiB	−5 B (−0.1%)	7.8 KiB	✅
Claude	Live turn WebSocket decoded	57.0 KiB	57.0 KiB	0 B (0.0%)	66.4 KiB	✅
Claude	Live turn messages	9	9	0 (0.0%)	21	✅

Baseline: 97fc049 · PR result: 3e7c550 · Source CI: success

Scenario and decoded snapshot size

10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 113.9 KiB
• Claude decoded thread snapshot: 114.6 KiB

Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.