Enforce resolved material access boundaries

[nahiyankhan]

Category: fix
User Impact: Hosts can enforce material-read permissions even when a bundled path is a symlink.

Problem: A bundled symlink could resolve outside the materials directory while retaining bundled permissions and inline limits.

Solution: Classify local material after resolving its real path. Require referenced-file permission and apply the referenced inline limit when the target leaves the materials directory; keep outside-repository targets unavailable.

Compatibility: Internal symlinks remain supported. Pull still inlines eligible referenced text by default; permission-sensitive hosts should use inlineMaterials: false before inspection.

Scope: Narrowed from the original 32-file PR to the material-access fix. The other four concerns have separate draft PRs; this branch targets main.

Related: Preserve guidance meaning in CLI output, Report incomplete guidance loading, Add read-only installed skill checks, Fix and validate rendered guidance examples.

Validation:

• pnpm run quality:all: passed on this standalone branch, including build, package/release checks, tests (231 passed), workspace builds, and package validations.
• Pre-commit checks and git diff origin/main...HEAD --check: passed.
• Fresh dependency installation hit registry checksum errors. Validation used an isolated copy of the existing checkout's dependencies; the lockfile is unchanged.

Changeset: Existing patch changeset retained.

ghost Review: Review packet assembled against apps/docs/.ghost. This package does not bind the changed CLI/test/docs files, so the packet is coverage context, not a passing brand review. Used the current ghost review --package apps/docs/.ghost --base origin/main --format json and inspected ghost manifest; the older ghost check, --include-memory, and dump:cli-help workflows are unavailable in this checkout.

File changes (6 files)

File	Purpose
.changeset/material-realpath-policy.md	Record the access-policy fix.
packages/ghost/README.md	Explain inspection permissions and pull's default inline behavior.
packages/ghost/src/embed/inspect.ts	Enforce inspection policy against the resolved material tier.
packages/ghost/src/ghost-core/material-transport.ts	Share realpath tier resolution and apply referenced inline limits.
packages/ghost/src/skill-bundle/references/schema.md	Document local material access boundaries.
packages/ghost/test/material-access.test.ts	Cover internal, escaping, and outside-repository symlinks, permissions, and limits.

Screenshots/Demos: N/A: no visual surface changes.