Migrated from Method backlog

This issue was created from a legacy filesystem backlog card. GitHub Issues are now the live work tracker; repository docs remain Method evidence.

Source backlog: docs/method/backlog/bad-code/PROCESS_workspace-initialization-signpost-aliases.md
Original lane: bad-code
Original legend: PROCESS
Original priority: high

Original backlog card

Workspace Initialization Should Accept Existing METHOD Signpost Aliases

Workspace.ensureInitialized() currently hard-codes the v2 signpost
layout:

CHANGELOG.md
docs/method/backlog/
docs/design/
docs/method/retro/
docs/PROCESS.md
docs/RELEASE.md

That makes MCP tools reject repos that have a valid METHOD filesystem
but use the older or repo-local signpost layout:

docs/METHOD.md
docs/method/process.md
docs/method/release.md

Observed symptom from git-warp:

/Users/james/git/git-stunts/git-warp is not a METHOD workspace.
Run `method init` first.

That repo has a real METHOD backlog, design directory, retro directory,
legends, and process docs. Running method init would be the wrong
advice because it would add generic scaffold signposts instead of
recognizing the existing repo-truth docs.

Required Test Fixture Shape

Write a unit test that creates this exact fixture tree:

workspace/
  CHANGELOG.md
  docs/
    METHOD.md
    design/
      .gitkeep
    method/
      process.md
      release.md
      backlog/
        inbox/
          .gitkeep
        asap/
          .gitkeep
        up-next/
          .gitkeep
        bad-code/
          .gitkeep
        cool-ideas/
          .gitkeep
      retro/
        .gitkeep
      graveyard/
        .gitkeep
      legends/
        .gitkeep

Do not create these files in the fixture:

docs/PROCESS.md
docs/RELEASE.md

The test should assert the existing fixture is accepted:

const workspace = new Workspace(root);

expect(() => workspace.status()).not.toThrow();

If the MCP surface is tested separately, call the same path through
method_status and assert ok: true.

Expected Fix Shape

Make initialization recognition accept either signpost set:

canonical v2:
  docs/PROCESS.md
  docs/RELEASE.md

existing alias layout:
  docs/METHOD.md
  docs/method/process.md
  docs/method/release.md

The shared structural requirements should remain:

CHANGELOG.md
docs/method/backlog/
docs/design/
docs/method/retro/

Do not weaken the workspace check into "any docs directory exists".
This should be a precise compatibility rule for real METHOD workspaces.

Error Message Improvement

When a workspace is truly uninitialized, report the missing paths rather
than only saying:

Run `method init` first.

Useful shape:

<root> is not a METHOD workspace.
Missing required paths:
- docs/method/backlog/
- docs/design/
- docs/method/retro/
Missing one required signpost set:
- docs/PROCESS.md + docs/RELEASE.md
- OR docs/METHOD.md + docs/method/process.md + docs/method/release.md

That lets agents distinguish "run init" from "this repo uses a valid
alternate signpost layout."