[takashi-matsuyama]

What

replayEvents and readAllEvents in @basou/core now take the store's paths and a session id instead of a session directory, and check the entry at the session's name, without following it, before reading:

Entry at .basou/sessions/<id>	Before	Now
a directory	read	read
nothing	nothing yielded	nothing yielded
a symlink, whatever it points to	read through it	SessionNotADirectoryError, kind symlink
a file, or anything else that is not a directory	Failed to read events.jsonl (ENOTDIR)	SessionNotADirectoryError, kind not_a_directory
a name that is not a session id	joined into a path	Invalid session id

A failed lstat of the entry gives Failed to read events.jsonl, without a path, with the native error as its cause, as the readers' other I/O failures do. The readers do not check .basou/sessions itself, so a federated mirror whose store is a symlink is still read; the local store is checked by the listing or resolver that produced the id.

SessionNotADirectoryError is new and exported from @basou/core, with sessionId and kind. assertSessionDirSafe, resolveSessionId and the readers throw it, and basou view's 404 takes its message, which is unchanged: Session <id> is not a directory; a symlink or a file there is not followed. The resolver takes the kind from the listing, so enumerateSessionEntries also returns symlinks, the entries of notDirectories that are symlinks.

@basou/sdk maps the refusal to null by the error's class instead of matching its message with a regular expression.

All 19 callers move to the new signature; the federated orientation passes each entry's own store.

Why

The readers relied on a convention: every caller had to pass an id from a listing or a check first. Every caller followed it, but nothing enforced it, and a new caller that forgot would read through a symlink. The refusal's message was also built in three places, and the SDK depended on it matching a regular expression.

User-visible behaviour

None in the CLI or the SDK, since every caller already passed a checked id. The readers' signature in @basou/core changes; core is not a semver-guaranteed API.

Docs

• CHANGELOG: three Unreleased "Changed" entries.

Verification

• pnpm -r build, pnpm -r typecheck, pnpm lint (the same 5 warnings and 1 info as main), pnpm lint:lang, pnpm lint:paths, and pnpm -r run test (core 2756 passed and 1 skipped, sdk 66, cli 1538): all exit 0.
• A separate review ran the CLI built from main and from this branch on the same fixtures (real sessions, a symlink to a copy of one, a file, a dangling symlink, a symlink to a file, pending approvals) across 88 invocations, and found no difference other than relative times and ports. The SDK across 12 inputs, and orient over a federated mirror whose store is a symlink, showed none either.
• Of 20 mutations tried against the first commit, the 4 that survived (checking the entry only after looking for events.jsonl, rethrowing the native lstat error, putting a path in its message, reversing symlinks) are caught by the tests the second commit adds.

Not in this PR

A symlink or a file that is not a regular file at events.jsonl or session.yaml inside a real session directory is still read through. A follow-up checks each file before reading it.