claude desktop: worktree sessions should inherit the base repo's .claude config

pairs with #76113 (fork into worktree) — once you're working in worktrees a lot, the worktree session loses the base repo's context

what

when a session runs inside a git worktree of a repo, it should inherit that repo's main .claude/ — CLAUDE.md, commands, settings/permissions — by default, instead of starting from a bare/minimal .claude in the worktree checkout

my real setup

i run worktree sessions across several submodules (.claude/worktrees/* exist in the root, dash, kizubot, store) — the worktrees each get their own minimal .claude and drop everything the base repo's .claude had

the pain

• worktree session doesn't see the base repo's CLAUDE.md (db schema conventions, api signatures, container-provisioning rules) — so it re-derives them or gets them wrong
• doesn't see the base repo's commands (deploy-bot, run-api-server) even though it's a worktree OF that repo
• re-approves the same permissions the base repo already had approved
• so every worktree/fork starts half-blind about a codebase it's literally a checkout of

ask

• worktree session inherits the base repo's .claude/ (CLAUDE.md + commands + settings/permissions) by default
• worktree-local .claude still overrides/extends on top (nearest wins)
• ideally the same for "fork into worktree" (#76113) — the fork keeps the parent repo's config, not just the conversation history

related: #76113, #76111