chore: post-review cleanup — docs drift, CONTEXT.md section order, review nits

[LeXwDeX]

Closes#374

What

Info-level findings from the two-axis review of 44c58434d..HEAD (both axes PASS, 0 blocking):

1. AGENTS.md — Git Workflow diagram/table/prose updated: dev PR gate is now Typecheck + Unit Tests (linux) (drift left by chore(ci): raise the dev PR gate to Typecheck + Unit Tests (linux) (middle-tier gating) #370's gate raise).
2. CONTEXT.md — the ## Conventions header from decide(dag): 'one live DAG per user goal' is documented as an Invariant but is an unenforced convention #348 was inserted mid-list and accidentally captured 5 original Invariants (model-facing schema, spec_path, legacy YAML, admission separation, and the engine-enforced gated-checkpoint/output_schema obligation). Section reordered: full Invariants list first, Conventions after. Those 5 are Invariants again.
3. memory-search.ts — identical if-branches folded back to ||.
4. blocks.ts — BLK-02 collision check extracted from the inline IIFE into aggregatorEvidenceMapping (Style Guide: supporting details in small named helpers).
5. fix(goal): GoalLoop not wired into server request-context node graph — standing goals stall on headless serve/web/desktop #340 acceptance delta documented — the "serve-mode goal continuing past turn 1" line is covered by composition (e2e-loop.test.ts behavior suite + the wiring probe asserting the exact failure class); no third harness is built.

Verification

• typecheck green; blocks tests 23/23; lint delta zero