Phat's Progression Framework

## v0.2.0

**Datapack support** — Mods can now ship tier definitions via datapack at `data/<namespace>/phats_progression/block_tiers/*.json` and `tool_tiers/*.json`. Modpack devs override defaults with `ignore_datapacks: true` in their configs.

**Mining feel improved** — Out-of-tier tools now mine at bare-hands speed instead of full speed. No more "block breaks but no drops" surprise.

**`/progression` debug command** — Inspect tier assignments in-game:
- `/progression info [item_id]` — held or named item's tier
- `/progression block [block_id]` — looking-at or named block's tier
- `/progression list tools|blocks` — dump all assignments to a file
- `/progression reload` — reload configs without restarting

**Vanilla tool fallback (1.21.1 only)** — Tools without explicit config entries now infer tier from `ToolMaterial`. Modded tools using vanilla tier values just work.

**Bug fixes**
- Tool type is now respected. Iron axe no longer mines iron ore — only pickaxes do, even when tiers match.
- 1.21.11 default config corrected to actually demonstrate copper-gates-iron progression.

**Breaking changes** — None. v0.1.0 configs continue to work; the new `ignore_datapacks` field defaults to `false` if missing.