[VSJoin-Exec] Rewrite Ch4/Ch5 to respond to Ch3 propositions

[ZeroJustMe]

Goal

Rewrite Chapter 4 and Chapter 5 so they respond directly to Chapter 3’s three ideas.

Required Restructure

• Ch4 organized by mechanism implementation evidence:
  • I: read/write decoupling runtime path
  • II: budgeted routing runtime path
  • III: control-plane/remap runtime path
• Ch5 organized by proposition-per-subsection:
  • P1 for Mechanism I
  • P2 for Mechanism II
  • P3 for Mechanism III
• Every conclusion contains boundary wording:
  • "in our implementation"
  • "under evaluated workloads"

Content Constraints

• Remove component-list style claims without measurable proposition.
• Add at least one negative/degradation result paragraph.
• Keep terms consistent: logical partition / AssignmentTable / rebalance.

Validation

• Cross-check each Ch5 claim against figure/table and config path.
• Ensure no claim depends on unavailable baseline implementation.
• latexmk compile pass.

Acceptance Criteria

• 3x3 mapping exists: Idea -> Ch4 implementation text -> Ch5 evidence.