refactor: codebase audit cleanup — dead code, dedup, module splits

Multi-agent audit + aggressive cleanup across server/web/coder/booterm,
delivered behind a DEFER discipline so none of the in-flight files were
touched. Removes dead code/deps/columns, dedups server + coder helpers,
and splits the oversized modules (tools.ts, opencode-server.ts,
sentinel-summaries, turn.ts, TerminalPane.tsx) behind stable contracts.
Adds 78 parity/unit tests (server 587, coder 323); fixes two latent bugs
(ChatPane queue keys, FileViewerOverlay blank-line parity).

Intended tag: v2.7.12-audit-cleanup.

apps/server/src/services/inference/turn-config.ts

@@ -0,0 +1,33 @@
+// P5 (SPLIT SKETCH 5): pure per-turn configuration resolved once at the top of
+// runAssistantTurn. No I/O — just the cap math + budget lookup so it can be
+// unit-tested without a DB or broker.
+
+import type { Agent } from '../../types/api.js';
+import { resolveToolBudget } from './budget.js';
+
+// v1.14.0: hard ceiling on the number of stream-and-tool iterations per
+// user-message turn. Per-agent cap via agent.steps is the primary knob;
+// MAX_STEPS is the safety ceiling. 200 is 4x the effective budget ceiling
+// (50 tool calls) — in practice budget fires first unless the model makes
+// many 0-tool-call iterations (which exit the loop via the non-tool finish
+// path anyway).
+export const MAX_STEPS = 200;
+
+export interface TurnConfig {
+  // min(agent.steps ?? Infinity, MAX_STEPS). The while loop runs while
+  // stepNumber < effectiveCap.
+  effectiveCap: number;
+  // cumulative tool-call budget for the turn (resolveToolBudget).
+  budget: number;
+  // effectiveCap === 0 → the model responds text-only (no tool execution).
+  isTextOnly: boolean;
+}
+
+export function resolveTurnConfig(agent: Agent | null): TurnConfig {
+  const budget = resolveToolBudget(agent);
+  // v1.14.0: effectiveCap = min(agent.steps ?? Infinity, MAX_STEPS).
+  // steps: 0 means "no tool calls allowed" — the first stream phase runs but
+  // any tool calls it emits are not executed (finalize as text-only).
+  const effectiveCap = Math.min(agent?.steps ?? Infinity, MAX_STEPS);
+  return { effectiveCap, budget, isTextOnly: effectiveCap === 0 };
+}