Pure helper functions for Review stage

[SorraTheOrc]

Implement pure, testable helper functions for Stage 3 Review:

• intensityIndex(label): Map intensity string to ordinal index (subtle=0, soft=1, medium=2, hard=3, aggressive=4)
• textureIndex(label): Map texture string to ordinal index (alphabetical: bright=0, crunchy=1, dark=2, harsh=3, noisy=4, sharp=5, smooth=6, tonal=7, warm=8)
• medianIntensity(selections): Compute median intensity index from a list of CandidateSelection
• medianTextureIndex(selections): For each entry, compute median index of its texture array; then compute median across entries
• flagCoherenceOutliers(selections): Return a Set of recipe names whose intensity or primary texture deviates >1 step from palette median; skip if <3 entries
• buildSummaryRows(selections, outliers): Format each selection into a table row [recipe, seed, category, intensity, texture, tags] with warning indicator for outliers
• summaryColumns: Table column definitions for the palette summary table

Acceptance Criteria:

• All functions are exported and testable in isolation
• intensityIndex returns correct ordinal for all 5 values plus -1 for unknown
• textureIndex returns correct ordinal for all 9 values plus -1 for unknown
• medianIntensity/medianTextureIndex return correct median for odd and even counts
• flagCoherenceOutliers correctly identifies entries deviating >1 step from median
• flagCoherenceOutliers returns empty set when <3 entries
• buildSummaryRows includes warning indicator for flagged entries