v1.14.0-outer-loop: explicit while loop replaces inference recursion

Converts the ad-hoc executeToolPhase → runAssistantTurn recursion into an
explicit while (stepNumber < effectiveCap) loop. A step is one stream-and-
tool-execute iteration; the loop terminates on non-tool finish, step-cap hit,
doom-loop, budget exhaustion, abort, or synthesis success.

MAX_STEPS = 200 hard ceiling (4x old effective limit from budget). Per-agent
steps: field in AGENTS.md frontmatter sets tighter caps (Refactorer: 5,
Architect: 20, others: unset = bounded only by MAX_STEPS). Resolution:
effectiveCap = Math.min(agent.steps ?? Infinity, MAX_STEPS).

executeToolPhase no longer recurses — returns ToolPhaseResult struct
(action: 'continue' | 'paused' | 'synthesis_done') so the caller decides
whether to continue or break. steps: 0 handled as "no tool calls allowed"
via runTextOnlyTurn (one text-only stream phase, tool calls ignored with
warn log).

Step-cap hits produce a sentinel summary (reuses cap_hit kind so
CapHitSentinel.tsx renders without frontend changes; text distinguishes
"Step limit reached" from "Tool budget exhausted"). Doom-loop check migrated
to top of loop body — same predicate, same threshold (3), break instead of
return.

step_start parts are in the schema CHECK but not emitted as message_parts —
writing before the stream phase creates a sequence-0 collision with
partsFromAssistantMessage. Structured log line emitted instead. Adversarial
review caught the collision pre-deploy.

332/332 server tests passing. No frontend changes. No schema changes.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/server/src/services/inference/index.ts

@@ -6,6 +6,7 @@
 
 export {
   createInferenceRunner,
+  MAX_STEPS,
   runAssistantTurn,
   runInference,
 } from './turn.js';
@@ -16,5 +17,6 @@ export type {
   StreamResult,
   TurnArgs,
 } from './turn.js';
+export type { ToolPhaseResult } from './tool-phase.js';
 export { detectDoomLoop, DOOM_LOOP_THRESHOLD } from './sentinels.js';
 export { buildMessagesPayload } from './payload.js';