Fix non-deterministic schedule friendly format comments in compiled workflows

[Copilot]

Schedule friendly format comments (e.g., # Friendly format: daily (scattered)) were appearing randomly in compiled workflows due to pointer address collisions across compilations.

Root Cause

The global scheduleFriendlyFormats map used frontmatter pointer addresses as keys via fmt.Sprintf("%p", frontmatter). When Go's memory allocator reused addresses, workflows retrieved formats from previous compilations:

// BAD: Global state with pointer-based keys
var scheduleFriendlyFormats = make(map[string]map[int]string)
friendlyFormatsKey := fmt.Sprintf("%p", frontmatter)
scheduleFriendlyFormats[friendlyFormatsKey] = formats

Changes

Move to per-compiler instance storage:

• Added scheduleFriendlyFormats map[int]string field to Compiler struct
• Reset c.scheduleFriendlyFormats = nil at compilation start
• Removed global variable and pointer-based key logic

// GOOD: Per-compilation instance state
type Compiler struct {
    // ...
    scheduleFriendlyFormats map[int]string
}

func (c *Compiler) CompileWorkflowData(...) error {
    c.scheduleFriendlyFormats = nil  // Reset per compilation
    // ...
}

Added determinism test:

• TestFriendlyFormatDeterminism validates no cross-compilation leakage

Original prompt

Investigate why this change happens random in compilation:

  # Friendly format: daily (scattered)

See https://github.com/githubnext/gh-aw/pull/11368/changes

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