Accept cross-directory instruction adapter symlinks in workspace topology

[phodal]

Problem

workspace-topology now accepts a tracked instruction symlink only when the link and its target sit in the same directory (PR #51, spec docs/specs/2026-08-02-contained-structural-symlinks.md). The dominant real-world convention is cross-directory: a single canonical root agent guide plus provider adapter links that point up one or two levels.

Verified against real Git fixtures on the PR #51 head:

Topology	Result
root CLAUDE.md -> AGENTS.md (same dir)	complete
packages/app/CLAUDE.md -> AGENTS.md (same dir)	complete
.github/copilot-instructions.md -> parent AGENTS.md	partial + structure-entry-unsafe
root CLAUDE.md -> absolute in-root AGENTS.md	partial + structure-entry-unsafe

Because scripts/harness-analysis/evidence-bundle/index.mjs treats any non-complete topology as fatal at normal depth, one adapter link makes the whole Evidence Bundle failed. Repositories using .claude/, .cursor/rules/, or .github/ adapter links therefore still cannot produce a normal Evidence Bundle after PR #51.

Why the current restriction may be stricter than needed

The redirect already requires: tracked provenance, a target that is itself a tracked instruction inventory entry, canonical containment in the topology root, a single relative hop (no chains), and a regular file. A .. hop does not weaken any of those guarantees — the target stays tracked and in-root.

Ownership is already attributed to the link's own route, which is where the coding agent actually reads the file, so a cross-directory link does not let one route fabricate another route's ownership.

Proposed acceptance criteria

• AC-1: A tracked instruction route whose relative single-hop target is a tracked instruction inventory entry inside the topology root resolves to complete, regardless of how many .. segments the link uses.
• AC-2: Chained links, escaping targets, ignored/untracked targets, non-structural targets, and manifest aliases stay rejected with structure-entry-unsafe.
• AC-3: The instruction scope is reported for the link's own route and provider, and the owner route stays derived from the link path, not the target path.
• AC-4: A normal Evidence Bundle completes for a repository whose only symlink is a cross-directory instruction adapter.
• AC-5: Decide explicitly whether an absolute link target inside the root is accepted, and document the choice.

Notes

Update the Non-goals section of docs/specs/2026-08-02-contained-structural-symlinks.md when this lands, since it currently records the cross-directory rejection as intended behavior.