fix(core): keep the recorded project name inside a git worktree

[joris-sevenlab]

What this changes

Inside a linked git worktree, battlestack now uses the project name recorded in .battlestack/manifest.json instead of the worktree's directory name. A rename of the main checkout is still detected and restamped as before.

Why

The project name came from path.basename(projectDir). Running any command in git worktree add ../my-app-feature was treated as a directory rename:

• the committed manifest's projectName was overwritten and the real name moved into previousNames
• pull, add and upgrade regenerated committed files with the worktree name: the package.json name, the compose name:, the AGENTS.md / README.md titles and the PWA manifest
• runtime checks (describe, port diagnosis, compose detection) looked for containers under the worktree name while docker-compose.yml still said the real one, which caused duplicate containers and errors
• cleanup in a worktree could list the main checkout's live containers and volumes as leftovers from a "previous name"

Type of change

• Bug fix

AI assistance

• Claude Code

Agent, service and model, if you know it: Claude Code, Opus 5.5

How much of this is agent-written?

• Substantial parts, with my own edits on top

Feature versions

• Not applicable

Testing

pnpm tsc
pnpm test   # 87 files, 990 passed, 1 skipped

packages/core/test/project-name.test.ts creates a real repo plus git worktree add in a tmp dir and checks:

• the name resolves to the recorded one in the worktree, from resolveProjectName and from buildRunContext
• neither reconcileProjectName nor writeManifest changes projectName or previousNames there
• a renamed main checkout still restamps
• a submodule-style .git file is not mistaken for a worktree

With the fix removed, the three worktree tests fail. The rename and detection tests keep passing.

• pnpm tsc passes
• pnpm test passes
• I removed the behaviour each new assertion covers, watched the test fail, and put it back

Checklist

• Scoped to one concern
• Public-facing docs updated where behaviour changed (docs/troubleshooting.md)
• No internal tracker numbers, post-mortem narrative, or internal infrastructure details in the diff
• No secrets, tokens or real credentials

Anything else

• A worktree now shares the compose project and hash-derived port defaults with the main checkout. That matches the name: already committed in docker-compose.yml. Fully isolated per-worktree stacks would be a separate feature.
• A worktree that was already broken by the old behaviour keeps the wrong name in its manifest. Reset .battlestack/manifest.json from main (or fix projectName and previousNames by hand) before running battlestack pull.
• A plain clone into a differently named folder still counts as a rename. That is unchanged.