feat(console): collapse Activity/MCP/Config into a Debug drawer (slice 6/6)

[brettchien]

Slice 6/6 of console-navigation-ia ADR (#83) — usercron adr83-impl runbook, per §7.6.

What

• Activity, MCP · oab-mcp, and Config (cluster/profile/region) come off the top-level #tabs strip and collapse into one secondary Debug drawer (#debug-drawer, slide-over from the right edge) — Part D: "implementation-detail surfaces... not part of the deploy/manage/chat journey."
• Opened by a [⚙]:
  • Per fleet row on the Fleets screen (7.2), scoped to that fleet — new, fleetButton() now renders a .fleets-row wrapper (select-button + gear as siblings, not nested buttons) instead of one giant row-button.
  • The Fleet detail header (7.3) — un-stubbed the existing disabled gear from slice 2.
• Internals unchanged: same three panes, same tab-switch behavior (now scoped to #debug-tabs instead of the old top-level #tabs), same "flag on new lines while hidden" indicator.
• Compose is the one surface left outside the drawer — with Activity/MCP/Config gone, it's the only thing left in that position, so it's now an always-visible section instead of a fourth peer tab. (Full removal of the standing Compose surface per Part C is still open — see feat(console): deploy actions — + New fleet / + Add instance (slice 5/6) #88's scoping note, unchanged here.)

Incidental bug fixes (same class as #82, both reintroduced by slice 1)

Found while touching this code again for the drawer move — not new work, but worth flagging since they were silent:

• id="config" collision: the Fleets-screen mount (<section id="config" class="config-wrap">) and the bottom Config pane both used id="config". main.ts's document.getElementById("config") always resolved to the first match (the Fleets screen) — so the Config tab pane main.ts was toggling hidden on was never the one with the actual form. Renamed the pane to debug-config.
• id="cfg-save" collision: the fleets.toml/registry TOML editor's Save button and the Config pane's own submit button both used id="cfg-save". config.ts's save-disable-while-saving logic was wired to the wrong button (the editor's, not its own). Renamed to debug-cfg-save.

Verification

• tsc --noEmit — clean
• vitest run — 107/107 passing (2 new/updated in render.test.ts covering the per-row and per-fleet-detail gear wiring)
• vite build — clean

Progress table: this is slice 6/6 — 1–6 all land after this merges. Runbook's step 6/7 (self-review pass across all six slices together) is next.

🤖 Generated by Orca (ecs-claude), usercron adr83-impl.