fix(sync): anchor --shared include entries to the mount root (BEA-5) (#56)

`bdrive init --shared wiki` wrote `include: ["wiki/"]`, which compile()
treats as an unanchored gitignore pattern — so any nested directory named
`wiki` synced too. Shared-subfolder mode is what people use to keep private
material out of a project, and it was silently widening the scope: 15 files
under .agents/, .claude/ and .gemini/ leaked into a real project from
.../detector/shared/ dirs.

cleanShared now emits "/wiki/", which fixes both callers (init --shared and
bdrive scope add). config.LoadProject anchors legacy single-segment entries
on read, so the existing mounts are fixed without a re-init — and that also
keeps `bdrive scope rm wiki` working against pre-fix configs, with a
belt-and-braces unanchored candidate key in scopeRemove for any config that
bypasses LoadProject.

Not touched: compile() itself, and no delete op for the already-leaked
remote files (BEA-20 — a delete would unlink teammates' local copies).

Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>

web/docs/src/content/docs/guides/scoping.md

@@ -29,9 +29,13 @@ The result lands in `.bdrive/config.json` as an include list:
 
 ```jsonc
 { "id": "m-5a10b713", "volume": "notes",
-  "remote": "https://drive.example.com/p/p-7f3a2c91", "include": ["wiki/"] }
+  "remote": "https://drive.example.com/p/p-7f3a2c91", "include": ["/wiki/"] }
 ```
 
+The leading slash anchors each entry to the mount root: `/wiki/` means the
+`wiki` folder at the top of this project and nothing else, so a nested
+directory that happens to share the name never syncs.
+
 ## Change the scope later
 
 `bdrive scope` shows the include list; `scope add` / `scope rm` edit it — no

web/docs/src/content/docs/reference/project-files.md

@@ -14,7 +14,7 @@ plus project, remote, and include settings.
 ```jsonc
 // .bdrive/config.json
 { "id": "m-5a10b713", "volume": "notes",
-  "remote": "https://drive.example.com/p/p-7f3a2c91", "include": ["shared/"] }
+  "remote": "https://drive.example.com/p/p-7f3a2c91", "include": ["/shared/"] }
 ```
 
 Written by `bdrive init` and safe to hand-edit — a running daemon picks changes