fix: declare @spacedevin/deck as a peer of both packages

[spacedevin]

The gen_block dialect registry is module-level mutable state — let dialects = {} in GenBlock.tish. A package that bundles its own copy of the language hands its consumer a second registry, so a dialect registered against one is invisible to the other. And because tish build inlines each import graph, two copies also collide every top-level symbol in the parser.

This is live, not theoretical

Deckard's main went red the moment it consumed the published catalog:

SyntaxError: Identifier 'normalizeGeneratorId' has already been declared

Its lockfile held @spacedevin/deck@1.6.2 while @spacedevin/deck-synths@1.8.0 declares ^1.8.0, so pnpm kept both on disk. spacedevin/deckard#16 pins the versions together as an immediate unblock; this is the fix that stops it recurring whenever the ranges drift.

Change

@spacedevin/deck moves from dependencies to peerDependencies in both packages/synths and packages/player, so the consumer supplies the single instance. It stays a devDependency (file:../..) so the workspace links locally, and both CI pack steps now stamp the peer range and drop the dev link.

Verified

Against a consumer deliberately pinned to the old ^1.6.2 range — the exact configuration that caused the collision:

• one copy of the language on disk, where there were previously two
• pnpm surfaces the skew as ✕ unmet peer @spacedevin/deck@^1.8.0: found 1.6.2 at install time, instead of a silent duplicate that explodes at build time

On the correct range: one copy, 968 assertions, 0 failures, no duplicate-declaration error.

Both suites in this repo unchanged — 8 language, 46 player.