Add Master Mod tables and lookup engine

[philoserf]

Summary

• add a generic named die-table engine (registry, contiguous and sparse lookup, deep-copy Get)
• preserve sparse and non-contiguous source rolls without inventing entries for blank cells; rows are book-literal text (including the seven <none> entries from p.267)
• transcribe 139 Master Mod tables (Book 1 pp.264-269), split by printed page into tables_p264.go … tables_p269.go with per-chart citations
• represent both printed Fantastic sub-columns (p.265) as "Technology Fantastic (Low)" 22-27 and "(High)" 28-33; Walk (p.266) carries the printed +4 Sonic / +5 Ssonic rows
• validate the full sorted name manifest, boundary behavior, sparse lookup, representative golden rows, and that every Dice notation is dice.Parse-able or on an exact-string allowlist (Bad Flux, 2x1D, Hits/2)
• document deliberate exclusions (Barrier H/W/D blanks, Scene Mods formula, unrolled Imperiallines/Hortalez rows) in the package CLAUDE.md

Validation

• task check
• git diff --check

Part of #181 (the issue also covers chargen background tables pp.92-97 and career muster-out tables, which this PR does not transcribe)

[philoserf]

Reviewed — leaving in draft, not merge-ready yet.

Two issues, one blocking on its own and one that's this batch's recurring pattern:

1. Confirmed transcription bug. internal/mastermod/tables.go:41-55, the Anatomical Damage Location table, rows 9-10: transcribed as "Limb-Group-3"/"Limb-Group-4", but Book 1 p.264 actually prints Limb-Grip-3/Limb-Grip-4 — distinct from rows 3-4's genuine Limb-Group-1/Limb-Group-2. Worse, mastermod_test.go:34's golden test asserts the wrong value ({9, "Limb-Group-3"}), so it locks in the error rather than catching it. (10 other spot-checked rows across different tables matched the book exactly — this looks like an isolated slip, not systemic, but the full 138-table set wasn't exhaustively re-verified.)
2. Orphan package. grep -rn mastermod outside internal/mastermod/ returns nothing — no CLI, no other package imports it. Same zero-consumer pattern already held back on Add travel-time kinematics #345 and Add shared benchmark scales #346 in this batch.

The lookup engine itself (Table/Lookup/sparse-rolls/substitution) is clean and well-tested. Suggest fixing the Grip/Group typo (and its golden test) and either wiring in a real first consumer or confirming primitive-first is intentional here before this comes out of draft.

[Copilot]

Pull request overview

This PR introduces a new internal/mastermod package that registers and serves the Traveller5 Book 1 (pp.264–269) “Master Mod / Typical Mods” named reference tables via a small lookup engine, including support for sparse/non-contiguous roll keys and a defensive-copy Get.

Changes:

• Added a table registry + lookup API (Table, Lookup, Get, Names) with support for both contiguous and sparse roll keying.
• Transcribed the Book 1 pp.264–269 tables into per-page Go files (tables_p264.go … tables_p269.go) with deliberate exclusions documented.
• Added tests covering name manifest stability, boundary/sparse lookup behavior, golden rows, and dice-notation parseability/allowlisting.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
internal/mastermod/mastermod.go	Core table type, registry, lookup logic, and public accessors (Get, Names).
internal/mastermod/mastermod_test.go	Validates registry inventory, lookup behavior, deep-copy semantics, and dice-notation rules.
internal/mastermod/tables_p264.go	Registers damage location tables from Book 1 p.264.
internal/mastermod/tables_p265.go	Registers Typical Mods charts 01–04 from Book 1 p.265 (including Fantastic split).
internal/mastermod/tables_p266.go	Registers Typical Mods charts 05–08 from Book 1 p.266 (including sparse Highway/Drive tables).
internal/mastermod/tables_p267.go	Registers Typical Mods charts 09–12 from Book 1 p.267 (including <none> rows).
internal/mastermod/tables_p268.go	Registers Typical Mods charts 13–16 from Book 1 p.268 (Senses + QREBS mods).
internal/mastermod/tables_p269.go	Registers Typical Mods charts 17–21 from Book 1 p.269 (including 2x1D MegaCorp/QREBS and extended severities).
internal/mastermod/CLAUDE.md	Documents scope, exclusions, and “do not fix” quirks for the transcription.

Suppressed comments (1)

internal/mastermod/tables_p268.go:255

• Spelling: "Burdensom" should be "Burdensome".

			"Very Burdensom",

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