Improve Runtime Console navigation and coding guidance - #309

Summary

• reorganize the Runtime Console so Session context has direct Overview / Activity / Details navigation and Runtime operations expose independent Overview / Runner fleet / Durable Agents destinations
• preserve in-progress forms while switching operations, improve focus/accessibility behavior, keep Recent Sessions visible by default, and fence delayed mobile-navigation focus
• simplify root repository agent guidance while preserving concrete safety, validation, Git, credential, and delivery boundaries and removing stale Session references
• strengthen WebCodex-owned built-in coding guidance so unnamed tasks receive useful defaults, nested path rules are explicit, review-only tasks do not implicitly authorize edits, and workflow/context projections remain bounded and schema-validated

Independent review / continuation

Recovered Codex session 01a0708d-f541-74c0-9ec7-1f30ac5a16f0 after its workspace quota ended and reviewed the existing work independently.

A real stop-point blocker was found: Codex had reduced the standalone workflow projection, but the complete work_on_project sparse payload still exceeded its existing budgets (fresh=4664 > 4300, unchanged=4763 > 4400). The guidance was compressed without widening those limits or dropping the authority/retry/review boundaries. Final values are fresh=4289 and unchanged=4388.

The generic test schema validator also now enforces minItems, so the new required workflow/default guidance arrays are actually tested against the declared output schema.

The branch was rebased cleanly onto 86fcf575 (Govern specialized Plugin and SSH invocations (#308)).

Validation

• cargo test -p webcodex --lib work_on_project -- --nocapture — 31 passed; fresh 4289 B, unchanged continuation 4388 B
• cargo test -p webcodex --lib builtin_coding_workflow -- --nocapture — 3 passed
• cargo test -p webcodex --lib startup_brief -- --nocapture — 22 passed; worst-case standard startup 30560 B
• cargo test -p webcodex --lib context_projection -- --nocapture — 6 passed
• cargo test -p webcodex-tool-contracts — 87 passed
• cargo check -p webcodex --lib — passed
• npm --prefix frontend run typecheck — passed
• npm --prefix frontend run check:dist — passed
• node --test frontend/test/runtime_console_state.test.mjs frontend/test/runtime_navigation.test.mjs — 32 passed
• cargo fmt --all -- --check — passed
• git diff --check origin/main...HEAD — passed

The original Codex UI pass also exercised mock-browser layouts from mobile through wide desktop, including context switching, keyboard reopen, operation selection/focus, horizontal overflow, and script-error checks.