fix: honor GHOST_PACKAGE_DIR in drift, ack, history, and review-command paths

[chailandau]

Why

Ghost supports relocating the fingerprint package via GHOST_PACKAGE_DIR (documented in SKILL.md for host wrappers and nested packages). But several commands still hardcoded the literal .ghost, so they ignored the configured directory. A repo whose package lives at, say, .agents/ghost/ works for init/scan/lint/verify/check/review, but silently breaks for drift, ack, diverge, compare --temporal, and the emit review-command footer.

This makes GHOST_PACKAGE_DIR resolution consistent across all local-package paths.

What

Replace hardcoded local-package .ghost literals with resolveGhostDirDefault() (which honors GHOST_PACKAGE_DIR and falls back to .ghost):

• evolution-commands.ts — loadLocalFingerprint() resolves the configured dir (fixes ack / diverge).
• drift-command.ts — local source fallback and the legacy fingerprint.md fallback resolve the configured dir.
• core/evolution/history.ts — appendHistory / readHistory write and read history.jsonl under the configured dir (fixes compare --temporal).
• context/package-review-command.ts — the emit footer's display fallback uses the configured dir.

Intentionally left as .ghost:

• The FINGERPRINT_PACKAGE_DIR constants — that is the upstream default resolveGhostDirDefault() returns when unset.
• node_modules/<pkg>/.ghost lookups — published npm packages ship their fingerprint at .ghost; a consumer's GHOST_PACKAGE_DIR does not apply to dependencies.

Tests

• New test/evolution/history-package-dir.test.ts: history writes to .ghost by default and to .agents/ghost when GHOST_PACKAGE_DIR is set (and not to .ghost).
• Full suite green: 411 tests passed.
• pnpm check green (biome, typecheck, file-size, docs, bundle, CLI manifest).
• Manual: GHOST_PACKAGE_DIR=.agents/ghost ghost init then ghost ack resolves the package from .agents/ghost (previously failed looking in .ghost); plain ghost init still defaults to .ghost.

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