PE hyperstack: codemode iron laws - no grep-shimming, no re-reads

[KailasMahavarkar]

Codemode had two context-discipline failures observed in live runs: greps were shimming in place of reads for files whose behaviour later gets asserted, and already-loaded files were being re-read after the phases completed. Both are the same failure class as the parallel-subagent bug fixed in #120 - a rule stated once in body prose does not hold. This applies the proven #120 fix pattern: Iron-Law salience plus repetition through the body.

Changes

Section	Intent
The Iron Law	2 new laws: GREP FOR INVENTORY, READ FOR UNDERSTANDING and NEVER RE-READ WHAT IS ALREADY IN CONTEXT
Loading discipline	"Two rules" -> "Four rules": new rule 2 (never grep-shim a read - grep answers inventory, reads answer meaning) and rule 3 (context window is the cache; re-read only on git status/git diff evidence of disk change)
Programmatic-first	renamed "Programmatic-first, bounded" - grep locates facts, it does not produce understanding
Phase 2	explicit: read load-bearing files whole, no grep-shimming files whose behaviour will be asserted
Post-Loading Discipline	new iron rule 12: answer all phases and follow-ups from loaded context, never re-read unchanged content

Before / After

Iron Law (before)                          Iron Law (after)
─────────────────────────────────────      ──────────────────────────────────────────────
PRESENT THE PLAN BEFORE LOADING            PRESENT THE PLAN BEFORE LOADING
RUN INLINE - NEVER DISPATCH SUBAGENTS      RUN INLINE - NEVER DISPATCH SUBAGENTS
                                           GREP FOR INVENTORY, READ FOR UNDERSTANDING -
                                             EXTRACTION NEVER REPLACES READING
                                           NEVER RE-READ WHAT IS ALREADY IN CONTEXT -
                                             THE CONTEXT WINDOW IS THE CACHE

Verification

• bun test: 85 pass, 0 fail (821 expects, 13 files)
• em-dash scan on edited file: clean
• skills INDEX and compiled bootstrap unaffected (frontmatter and hyperstack SKILL.md untouched)