Site 1 (config root): under memberHerdrSocket, writeConfig() now places the
ephemeral opencode.json directory under worktreeRoot and shares it read-only
with worktreeGroup, reusing EnvAllowListScrub#shareWithGroup (widened to
package-private and generalized) — the same mechanism #213 built for the
ZDOTDIR scrub, rather than a second copy. Unlike the ZDOTDIR scrub's
degrade-to-overlay fallback, a missing worktreeRoot/worktreeGroup here
REFUSES the spawn (IllegalStateException from buildLaunch): this file is the
member's only way to learn where the bridge MCP is, so writing it somewhere
unreadable would just produce an undeliverable member with no signal
pointing at the cause. memberHerdrSocket absent stays byte-identical.
Site 2 (discovery root): under memberHerdrSocket, agentSessionId() now
declares session discovery unavailable and logs one WARN per launcher
instance instead of silently scanning fleetd's own $HOME (opencode.db lives
under the MEMBER's home under this config key). Decision + reasoning for why
this is a declare-unavailable rather than a new config key is in
defaultDiscoveryRoot()'s javadoc.
Widened HerdrPeerLauncher#memberHerdrSocketConfigured/memberScrubParentDir/
memberGroup to package-private so OpenCodeLauncher reuses the exact same
config resolution rather than re-deriving it.
Same-shape finding (not fixed, out of scope): ClaudeCodeLauncher#writeCharterFile
(line ~465) writes the role-charter temp file via Files.createTempFile with no
directory argument, i.e. under java.io.tmpdir — the same site-1 shape, unfixed
for the Claude Code adapter.